diff --git a/vendor/github.com/json-iterator/go/config.go b/vendor/github.com/json-iterator/go/config.go
new file mode 100644
index 0000000..8c58fcb
--- /dev/null
+++ b/vendor/github.com/json-iterator/go/config.go
@@ -0,0 +1,375 @@
+package jsoniter
+
+import (
+	"encoding/json"
+	"io"
+	"reflect"
+	"sync"
+	"unsafe"
+
+	"github.com/modern-go/concurrent"
+	"github.com/modern-go/reflect2"
+)
+
+// Config customize how the API should behave.
+// The API is created from Config by Froze.
+type Config struct {
+	IndentionStep                 int
+	MarshalFloatWith6Digits       bool
+	EscapeHTML                    bool
+	SortMapKeys                   bool
+	UseNumber                     bool
+	DisallowUnknownFields         bool
+	TagKey                        string
+	OnlyTaggedField               bool
+	ValidateJsonRawMessage        bool
+	ObjectFieldMustBeSimpleString bool
+	CaseSensitive                 bool
+}
+
+// API the public interface of this package.
+// Primary Marshal and Unmarshal.
+type API interface {
+	IteratorPool
+	StreamPool
+	MarshalToString(v interface{}) (string, error)
+	Marshal(v interface{}) ([]byte, error)
+	MarshalIndent(v interface{}, prefix, indent string) ([]byte, error)
+	UnmarshalFromString(str string, v interface{}) error
+	Unmarshal(data []byte, v interface{}) error
+	Get(data []byte, path ...interface{}) Any
+	NewEncoder(writer io.Writer) *Encoder
+	NewDecoder(reader io.Reader) *Decoder
+	Valid(data []byte) bool
+	RegisterExtension(extension Extension)
+	DecoderOf(typ reflect2.Type) ValDecoder
+	EncoderOf(typ reflect2.Type) ValEncoder
+}
+
+// ConfigDefault the default API
+var ConfigDefault = Config{
+	EscapeHTML: true,
+}.Froze()
+
+// ConfigCompatibleWithStandardLibrary tries to be 100% compatible with standard library behavior
+var ConfigCompatibleWithStandardLibrary = Config{
+	EscapeHTML:             true,
+	SortMapKeys:            true,
+	ValidateJsonRawMessage: true,
+}.Froze()
+
+// ConfigFastest marshals float with only 6 digits precision
+var ConfigFastest = Config{
+	EscapeHTML:                    false,
+	MarshalFloatWith6Digits:       true, // will lose precession
+	ObjectFieldMustBeSimpleString: true, // do not unescape object field
+}.Froze()
+
+type frozenConfig struct {
+	configBeforeFrozen            Config
+	sortMapKeys                   bool
+	indentionStep                 int
+	objectFieldMustBeSimpleString bool
+	onlyTaggedField               bool
+	disallowUnknownFields         bool
+	decoderCache                  *concurrent.Map
+	encoderCache                  *concurrent.Map
+	encoderExtension              Extension
+	decoderExtension              Extension
+	extraExtensions               []Extension
+	streamPool                    *sync.Pool
+	iteratorPool                  *sync.Pool
+	caseSensitive                 bool
+}
+
+func (cfg *frozenConfig) initCache() {
+	cfg.decoderCache = concurrent.NewMap()
+	cfg.encoderCache = concurrent.NewMap()
+}
+
+func (cfg *frozenConfig) addDecoderToCache(cacheKey uintptr, decoder ValDecoder) {
+	cfg.decoderCache.Store(cacheKey, decoder)
+}
+
+func (cfg *frozenConfig) addEncoderToCache(cacheKey uintptr, encoder ValEncoder) {
+	cfg.encoderCache.Store(cacheKey, encoder)
+}
+
+func (cfg *frozenConfig) getDecoderFromCache(cacheKey uintptr) ValDecoder {
+	decoder, found := cfg.decoderCache.Load(cacheKey)
+	if found {
+		return decoder.(ValDecoder)
+	}
+	return nil
+}
+
+func (cfg *frozenConfig) getEncoderFromCache(cacheKey uintptr) ValEncoder {
+	encoder, found := cfg.encoderCache.Load(cacheKey)
+	if found {
+		return encoder.(ValEncoder)
+	}
+	return nil
+}
+
+var cfgCache = concurrent.NewMap()
+
+func getFrozenConfigFromCache(cfg Config) *frozenConfig {
+	obj, found := cfgCache.Load(cfg)
+	if found {
+		return obj.(*frozenConfig)
+	}
+	return nil
+}
+
+func addFrozenConfigToCache(cfg Config, frozenConfig *frozenConfig) {
+	cfgCache.Store(cfg, frozenConfig)
+}
+
+// Froze forge API from config
+func (cfg Config) Froze() API {
+	api := &frozenConfig{
+		sortMapKeys:                   cfg.SortMapKeys,
+		indentionStep:                 cfg.IndentionStep,
+		objectFieldMustBeSimpleString: cfg.ObjectFieldMustBeSimpleString,
+		onlyTaggedField:               cfg.OnlyTaggedField,
+		disallowUnknownFields:         cfg.DisallowUnknownFields,
+		caseSensitive:                 cfg.CaseSensitive,
+	}
+	api.streamPool = &sync.Pool{
+		New: func() interface{} {
+			return NewStream(api, nil, 512)
+		},
+	}
+	api.iteratorPool = &sync.Pool{
+		New: func() interface{} {
+			return NewIterator(api)
+		},
+	}
+	api.initCache()
+	encoderExtension := EncoderExtension{}
+	decoderExtension := DecoderExtension{}
+	if cfg.MarshalFloatWith6Digits {
+		api.marshalFloatWith6Digits(encoderExtension)
+	}
+	if cfg.EscapeHTML {
+		api.escapeHTML(encoderExtension)
+	}
+	if cfg.UseNumber {
+		api.useNumber(decoderExtension)
+	}
+	if cfg.ValidateJsonRawMessage {
+		api.validateJsonRawMessage(encoderExtension)
+	}
+	api.encoderExtension = encoderExtension
+	api.decoderExtension = decoderExtension
+	api.configBeforeFrozen = cfg
+	return api
+}
+
+func (cfg Config) frozeWithCacheReuse(extraExtensions []Extension) *frozenConfig {
+	api := getFrozenConfigFromCache(cfg)
+	if api != nil {
+		return api
+	}
+	api = cfg.Froze().(*frozenConfig)
+	for _, extension := range extraExtensions {
+		api.RegisterExtension(extension)
+	}
+	addFrozenConfigToCache(cfg, api)
+	return api
+}
+
+func (cfg *frozenConfig) validateJsonRawMessage(extension EncoderExtension) {
+	encoder := &funcEncoder{func(ptr unsafe.Pointer, stream *Stream) {
+		rawMessage := *(*json.RawMessage)(ptr)
+		iter := cfg.BorrowIterator([]byte(rawMessage))
+		iter.Read()
+		if iter.Error != nil {
+			stream.WriteRaw("null")
+		} else {
+			cfg.ReturnIterator(iter)
+			stream.WriteRaw(string(rawMessage))
+		}
+	}, func(ptr unsafe.Pointer) bool {
+		return len(*((*json.RawMessage)(ptr))) == 0
+	}}
+	extension[reflect2.TypeOfPtr((*json.RawMessage)(nil)).Elem()] = encoder
+	extension[reflect2.TypeOfPtr((*RawMessage)(nil)).Elem()] = encoder
+}
+
+func (cfg *frozenConfig) useNumber(extension DecoderExtension) {
+	extension[reflect2.TypeOfPtr((*interface{})(nil)).Elem()] = &funcDecoder{func(ptr unsafe.Pointer, iter *Iterator) {
+		exitingValue := *((*interface{})(ptr))
+		if exitingValue != nil && reflect.TypeOf(exitingValue).Kind() == reflect.Ptr {
+			iter.ReadVal(exitingValue)
+			return
+		}
+		if iter.WhatIsNext() == NumberValue {
+			*((*interface{})(ptr)) = json.Number(iter.readNumberAsString())
+		} else {
+			*((*interface{})(ptr)) = iter.Read()
+		}
+	}}
+}
+func (cfg *frozenConfig) getTagKey() string {
+	tagKey := cfg.configBeforeFrozen.TagKey
+	if tagKey == "" {
+		return "json"
+	}
+	return tagKey
+}
+
+func (cfg *frozenConfig) RegisterExtension(extension Extension) {
+	cfg.extraExtensions = append(cfg.extraExtensions, extension)
+	copied := cfg.configBeforeFrozen
+	cfg.configBeforeFrozen = copied
+}
+
+type lossyFloat32Encoder struct {
+}
+
+func (encoder *lossyFloat32Encoder) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteFloat32Lossy(*((*float32)(ptr)))
+}
+
+func (encoder *lossyFloat32Encoder) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*float32)(ptr)) == 0
+}
+
+type lossyFloat64Encoder struct {
+}
+
+func (encoder *lossyFloat64Encoder) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteFloat64Lossy(*((*float64)(ptr)))
+}
+
+func (encoder *lossyFloat64Encoder) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*float64)(ptr)) == 0
+}
+
+// EnableLossyFloatMarshalling keeps 10**(-6) precision
+// for float variables for better performance.
+func (cfg *frozenConfig) marshalFloatWith6Digits(extension EncoderExtension) {
+	// for better performance
+	extension[reflect2.TypeOfPtr((*float32)(nil)).Elem()] = &lossyFloat32Encoder{}
+	extension[reflect2.TypeOfPtr((*float64)(nil)).Elem()] = &lossyFloat64Encoder{}
+}
+
+type htmlEscapedStringEncoder struct {
+}
+
+func (encoder *htmlEscapedStringEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
+	str := *((*string)(ptr))
+	stream.WriteStringWithHTMLEscaped(str)
+}
+
+func (encoder *htmlEscapedStringEncoder) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*string)(ptr)) == ""
+}
+
+func (cfg *frozenConfig) escapeHTML(encoderExtension EncoderExtension) {
+	encoderExtension[reflect2.TypeOfPtr((*string)(nil)).Elem()] = &htmlEscapedStringEncoder{}
+}
+
+func (cfg *frozenConfig) cleanDecoders() {
+	typeDecoders = map[string]ValDecoder{}
+	fieldDecoders = map[string]ValDecoder{}
+	*cfg = *(cfg.configBeforeFrozen.Froze().(*frozenConfig))
+}
+
+func (cfg *frozenConfig) cleanEncoders() {
+	typeEncoders = map[string]ValEncoder{}
+	fieldEncoders = map[string]ValEncoder{}
+	*cfg = *(cfg.configBeforeFrozen.Froze().(*frozenConfig))
+}
+
+func (cfg *frozenConfig) MarshalToString(v interface{}) (string, error) {
+	stream := cfg.BorrowStream(nil)
+	defer cfg.ReturnStream(stream)
+	stream.WriteVal(v)
+	if stream.Error != nil {
+		return "", stream.Error
+	}
+	return string(stream.Buffer()), nil
+}
+
+func (cfg *frozenConfig) Marshal(v interface{}) ([]byte, error) {
+	stream := cfg.BorrowStream(nil)
+	defer cfg.ReturnStream(stream)
+	stream.WriteVal(v)
+	if stream.Error != nil {
+		return nil, stream.Error
+	}
+	result := stream.Buffer()
+	copied := make([]byte, len(result))
+	copy(copied, result)
+	return copied, nil
+}
+
+func (cfg *frozenConfig) MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
+	if prefix != "" {
+		panic("prefix is not supported")
+	}
+	for _, r := range indent {
+		if r != ' ' {
+			panic("indent can only be space")
+		}
+	}
+	newCfg := cfg.configBeforeFrozen
+	newCfg.IndentionStep = len(indent)
+	return newCfg.frozeWithCacheReuse(cfg.extraExtensions).Marshal(v)
+}
+
+func (cfg *frozenConfig) UnmarshalFromString(str string, v interface{}) error {
+	data := []byte(str)
+	iter := cfg.BorrowIterator(data)
+	defer cfg.ReturnIterator(iter)
+	iter.ReadVal(v)
+	c := iter.nextToken()
+	if c == 0 {
+		if iter.Error == io.EOF {
+			return nil
+		}
+		return iter.Error
+	}
+	iter.ReportError("Unmarshal", "there are bytes left after unmarshal")
+	return iter.Error
+}
+
+func (cfg *frozenConfig) Get(data []byte, path ...interface{}) Any {
+	iter := cfg.BorrowIterator(data)
+	defer cfg.ReturnIterator(iter)
+	return locatePath(iter, path)
+}
+
+func (cfg *frozenConfig) Unmarshal(data []byte, v interface{}) error {
+	iter := cfg.BorrowIterator(data)
+	defer cfg.ReturnIterator(iter)
+	iter.ReadVal(v)
+	c := iter.nextToken()
+	if c == 0 {
+		if iter.Error == io.EOF {
+			return nil
+		}
+		return iter.Error
+	}
+	iter.ReportError("Unmarshal", "there are bytes left after unmarshal")
+	return iter.Error
+}
+
+func (cfg *frozenConfig) NewEncoder(writer io.Writer) *Encoder {
+	stream := NewStream(cfg, writer, 512)
+	return &Encoder{stream}
+}
+
+func (cfg *frozenConfig) NewDecoder(reader io.Reader) *Decoder {
+	iter := Parse(cfg, reader, 512)
+	return &Decoder{iter}
+}
+
+func (cfg *frozenConfig) Valid(data []byte) bool {
+	iter := cfg.BorrowIterator(data)
+	defer cfg.ReturnIterator(iter)
+	iter.Skip()
+	return iter.Error == nil
+}