diff --git a/vendor/github.com/mongodb/mongo-go-driver/bson/bsoncodec/struct_codec.go b/vendor/github.com/mongodb/mongo-go-driver/bson/bsoncodec/struct_codec.go
new file mode 100644
index 0000000..34f3b4c
--- /dev/null
+++ b/vendor/github.com/mongodb/mongo-go-driver/bson/bsoncodec/struct_codec.go
@@ -0,0 +1,357 @@
+// Copyright (C) MongoDB, Inc. 2017-present.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package bsoncodec
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"sync"
+
+	"github.com/mongodb/mongo-go-driver/bson/bsonrw"
+	"github.com/mongodb/mongo-go-driver/bson/bsontype"
+)
+
+var defaultStructCodec = &StructCodec{
+	cache:  make(map[reflect.Type]*structDescription),
+	parser: DefaultStructTagParser,
+}
+
+// Zeroer allows custom struct types to implement a report of zero
+// state. All struct types that don't implement Zeroer or where IsZero
+// returns false are considered to be not zero.
+type Zeroer interface {
+	IsZero() bool
+}
+
+// StructCodec is the Codec used for struct values.
+type StructCodec struct {
+	cache  map[reflect.Type]*structDescription
+	l      sync.RWMutex
+	parser StructTagParser
+}
+
+var _ ValueEncoder = &StructCodec{}
+var _ ValueDecoder = &StructCodec{}
+
+// NewStructCodec returns a StructCodec that uses p for struct tag parsing.
+func NewStructCodec(p StructTagParser) (*StructCodec, error) {
+	if p == nil {
+		return nil, errors.New("a StructTagParser must be provided to NewStructCodec")
+	}
+
+	return &StructCodec{
+		cache:  make(map[reflect.Type]*structDescription),
+		parser: p,
+	}, nil
+}
+
+// EncodeValue handles encoding generic struct types.
+func (sc *StructCodec) EncodeValue(r EncodeContext, vw bsonrw.ValueWriter, val reflect.Value) error {
+	if !val.IsValid() || val.Kind() != reflect.Struct {
+		return ValueEncoderError{Name: "StructCodec.EncodeValue", Kinds: []reflect.Kind{reflect.Struct}, Received: val}
+	}
+
+	sd, err := sc.describeStruct(r.Registry, val.Type())
+	if err != nil {
+		return err
+	}
+
+	dw, err := vw.WriteDocument()
+	if err != nil {
+		return err
+	}
+	var rv reflect.Value
+	for _, desc := range sd.fl {
+		if desc.inline == nil {
+			rv = val.Field(desc.idx)
+		} else {
+			rv = val.FieldByIndex(desc.inline)
+		}
+
+		if desc.encoder == nil {
+			return ErrNoEncoder{Type: rv.Type()}
+		}
+
+		encoder := desc.encoder
+
+		iszero := sc.isZero
+		if iz, ok := encoder.(CodecZeroer); ok {
+			iszero = iz.IsTypeZero
+		}
+
+		if desc.omitEmpty && iszero(rv.Interface()) {
+			continue
+		}
+
+		vw2, err := dw.WriteDocumentElement(desc.name)
+		if err != nil {
+			return err
+		}
+
+		ectx := EncodeContext{Registry: r.Registry, MinSize: desc.minSize}
+		err = encoder.EncodeValue(ectx, vw2, rv)
+		if err != nil {
+			return err
+		}
+	}
+
+	if sd.inlineMap >= 0 {
+		rv := val.Field(sd.inlineMap)
+		collisionFn := func(key string) bool {
+			_, exists := sd.fm[key]
+			return exists
+		}
+
+		return defaultValueEncoders.mapEncodeValue(r, dw, rv, collisionFn)
+	}
+
+	return dw.WriteDocumentEnd()
+}
+
+// DecodeValue implements the Codec interface.
+func (sc *StructCodec) DecodeValue(r DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
+	if !val.CanSet() || val.Kind() != reflect.Struct {
+		return ValueDecoderError{Name: "StructCodec.DecodeValue", Kinds: []reflect.Kind{reflect.Struct}, Received: val}
+	}
+
+	switch vr.Type() {
+	case bsontype.Type(0), bsontype.EmbeddedDocument:
+	default:
+		return fmt.Errorf("cannot decode %v into a %s", vr.Type(), val.Type())
+	}
+
+	sd, err := sc.describeStruct(r.Registry, val.Type())
+	if err != nil {
+		return err
+	}
+
+	var decoder ValueDecoder
+	var inlineMap reflect.Value
+	if sd.inlineMap >= 0 {
+		inlineMap = val.Field(sd.inlineMap)
+		if inlineMap.IsNil() {
+			inlineMap.Set(reflect.MakeMap(inlineMap.Type()))
+		}
+		decoder, err = r.LookupDecoder(inlineMap.Type().Elem())
+		if err != nil {
+			return err
+		}
+	}
+
+	dr, err := vr.ReadDocument()
+	if err != nil {
+		return err
+	}
+
+	for {
+		name, vr, err := dr.ReadElement()
+		if err == bsonrw.ErrEOD {
+			break
+		}
+		if err != nil {
+			return err
+		}
+
+		fd, exists := sd.fm[name]
+		if !exists {
+			if sd.inlineMap < 0 {
+				// The encoding/json package requires a flag to return on error for non-existent fields.
+				// This functionality seems appropriate for the struct codec.
+				err = vr.Skip()
+				if err != nil {
+					return err
+				}
+				continue
+			}
+
+			elem := reflect.New(inlineMap.Type().Elem()).Elem()
+			err = decoder.DecodeValue(r, vr, elem)
+			if err != nil {
+				return err
+			}
+			inlineMap.SetMapIndex(reflect.ValueOf(name), elem)
+			continue
+		}
+
+		var field reflect.Value
+		if fd.inline == nil {
+			field = val.Field(fd.idx)
+		} else {
+			field = val.FieldByIndex(fd.inline)
+		}
+
+		if !field.CanSet() { // Being settable is a super set of being addressable.
+			return fmt.Errorf("cannot decode element '%s' into field %v; it is not settable", name, field)
+		}
+		if field.Kind() == reflect.Ptr && field.IsNil() {
+			field.Set(reflect.New(field.Type().Elem()))
+		}
+		field = field.Addr()
+
+		dctx := DecodeContext{Registry: r.Registry, Truncate: fd.truncate}
+		if fd.decoder == nil {
+			return ErrNoDecoder{Type: field.Elem().Type()}
+		}
+
+		if decoder, ok := fd.decoder.(ValueDecoder); ok {
+			err = decoder.DecodeValue(dctx, vr, field.Elem())
+			if err != nil {
+				return err
+			}
+			continue
+		}
+		err = fd.decoder.DecodeValue(dctx, vr, field)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (sc *StructCodec) isZero(i interface{}) bool {
+	v := reflect.ValueOf(i)
+
+	// check the value validity
+	if !v.IsValid() {
+		return true
+	}
+
+	if z, ok := v.Interface().(Zeroer); ok && (v.Kind() != reflect.Ptr || !v.IsNil()) {
+		return z.IsZero()
+	}
+
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+
+	return false
+}
+
+type structDescription struct {
+	fm        map[string]fieldDescription
+	fl        []fieldDescription
+	inlineMap int
+}
+
+type fieldDescription struct {
+	name      string
+	idx       int
+	omitEmpty bool
+	minSize   bool
+	truncate  bool
+	inline    []int
+	encoder   ValueEncoder
+	decoder   ValueDecoder
+}
+
+func (sc *StructCodec) describeStruct(r *Registry, t reflect.Type) (*structDescription, error) {
+	// We need to analyze the struct, including getting the tags, collecting
+	// information about inlining, and create a map of the field name to the field.
+	sc.l.RLock()
+	ds, exists := sc.cache[t]
+	sc.l.RUnlock()
+	if exists {
+		return ds, nil
+	}
+
+	numFields := t.NumField()
+	sd := &structDescription{
+		fm:        make(map[string]fieldDescription, numFields),
+		fl:        make([]fieldDescription, 0, numFields),
+		inlineMap: -1,
+	}
+
+	for i := 0; i < numFields; i++ {
+		sf := t.Field(i)
+		if sf.PkgPath != "" {
+			// unexported, ignore
+			continue
+		}
+
+		encoder, err := r.LookupEncoder(sf.Type)
+		if err != nil {
+			encoder = nil
+		}
+		decoder, err := r.LookupDecoder(sf.Type)
+		if err != nil {
+			decoder = nil
+		}
+
+		description := fieldDescription{idx: i, encoder: encoder, decoder: decoder}
+
+		stags, err := sc.parser.ParseStructTags(sf)
+		if err != nil {
+			return nil, err
+		}
+		if stags.Skip {
+			continue
+		}
+		description.name = stags.Name
+		description.omitEmpty = stags.OmitEmpty
+		description.minSize = stags.MinSize
+		description.truncate = stags.Truncate
+
+		if stags.Inline {
+			switch sf.Type.Kind() {
+			case reflect.Map:
+				if sd.inlineMap >= 0 {
+					return nil, errors.New("(struct " + t.String() + ") multiple inline maps")
+				}
+				if sf.Type.Key() != tString {
+					return nil, errors.New("(struct " + t.String() + ") inline map must have a string keys")
+				}
+				sd.inlineMap = description.idx
+			case reflect.Struct:
+				inlinesf, err := sc.describeStruct(r, sf.Type)
+				if err != nil {
+					return nil, err
+				}
+				for _, fd := range inlinesf.fl {
+					if _, exists := sd.fm[fd.name]; exists {
+						return nil, fmt.Errorf("(struct %s) duplicated key %s", t.String(), fd.name)
+					}
+					if fd.inline == nil {
+						fd.inline = []int{i, fd.idx}
+					} else {
+						fd.inline = append([]int{i}, fd.inline...)
+					}
+					sd.fm[fd.name] = fd
+					sd.fl = append(sd.fl, fd)
+				}
+			default:
+				return nil, fmt.Errorf("(struct %s) inline fields must be either a struct or a map", t.String())
+			}
+			continue
+		}
+
+		if _, exists := sd.fm[description.name]; exists {
+			return nil, fmt.Errorf("struct %s) duplicated key %s", t.String(), description.name)
+		}
+
+		sd.fm[description.name] = description
+		sd.fl = append(sd.fl, description)
+	}
+
+	sc.l.Lock()
+	sc.cache[t] = sd
+	sc.l.Unlock()
+
+	return sd, nil
+}