diff --git a/vendor/github.com/jessevdk/go-flags/option.go b/vendor/github.com/jessevdk/go-flags/option.go
new file mode 100644
index 0000000..5f85250
--- /dev/null
+++ b/vendor/github.com/jessevdk/go-flags/option.go
@@ -0,0 +1,459 @@
+package flags
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"reflect"
+	"strings"
+	"unicode/utf8"
+)
+
+// Option flag information. Contains a description of the option, short and
+// long name as well as a default value and whether an argument for this
+// flag is optional.
+type Option struct {
+	// The description of the option flag. This description is shown
+	// automatically in the built-in help.
+	Description string
+
+	// The short name of the option (a single character). If not 0, the
+	// option flag can be 'activated' using -<ShortName>. Either ShortName
+	// or LongName needs to be non-empty.
+	ShortName rune
+
+	// The long name of the option. If not "", the option flag can be
+	// activated using --<LongName>. Either ShortName or LongName needs
+	// to be non-empty.
+	LongName string
+
+	// The default value of the option.
+	Default []string
+
+	// The optional environment default value key name.
+	EnvDefaultKey string
+
+	// The optional delimiter string for EnvDefaultKey values.
+	EnvDefaultDelim string
+
+	// If true, specifies that the argument to an option flag is optional.
+	// When no argument to the flag is specified on the command line, the
+	// value of OptionalValue will be set in the field this option represents.
+	// This is only valid for non-boolean options.
+	OptionalArgument bool
+
+	// The optional value of the option. The optional value is used when
+	// the option flag is marked as having an OptionalArgument. This means
+	// that when the flag is specified, but no option argument is given,
+	// the value of the field this option represents will be set to
+	// OptionalValue. This is only valid for non-boolean options.
+	OptionalValue []string
+
+	// If true, the option _must_ be specified on the command line. If the
+	// option is not specified, the parser will generate an ErrRequired type
+	// error.
+	Required bool
+
+	// A name for the value of an option shown in the Help as --flag [ValueName]
+	ValueName string
+
+	// A mask value to show in the help instead of the default value. This
+	// is useful for hiding sensitive information in the help, such as
+	// passwords.
+	DefaultMask string
+
+	// If non empty, only a certain set of values is allowed for an option.
+	Choices []string
+
+	// If true, the option is not displayed in the help or man page
+	Hidden bool
+
+	// The group which the option belongs to
+	group *Group
+
+	// The struct field which the option represents.
+	field reflect.StructField
+
+	// The struct field value which the option represents.
+	value reflect.Value
+
+	// Determines if the option will be always quoted in the INI output
+	iniQuote bool
+
+	tag            multiTag
+	isSet          bool
+	isSetDefault   bool
+	preventDefault bool
+
+	defaultLiteral string
+}
+
+// LongNameWithNamespace returns the option's long name with the group namespaces
+// prepended by walking up the option's group tree. Namespaces and the long name
+// itself are separated by the parser's namespace delimiter. If the long name is
+// empty an empty string is returned.
+func (option *Option) LongNameWithNamespace() string {
+	if len(option.LongName) == 0 {
+		return ""
+	}
+
+	// fetch the namespace delimiter from the parser which is always at the
+	// end of the group hierarchy
+	namespaceDelimiter := ""
+	g := option.group
+
+	for {
+		if p, ok := g.parent.(*Parser); ok {
+			namespaceDelimiter = p.NamespaceDelimiter
+
+			break
+		}
+
+		switch i := g.parent.(type) {
+		case *Command:
+			g = i.Group
+		case *Group:
+			g = i
+		}
+	}
+
+	// concatenate long name with namespace
+	longName := option.LongName
+	g = option.group
+
+	for g != nil {
+		if g.Namespace != "" {
+			longName = g.Namespace + namespaceDelimiter + longName
+		}
+
+		switch i := g.parent.(type) {
+		case *Command:
+			g = i.Group
+		case *Group:
+			g = i
+		case *Parser:
+			g = nil
+		}
+	}
+
+	return longName
+}
+
+// String converts an option to a human friendly readable string describing the
+// option.
+func (option *Option) String() string {
+	var s string
+	var short string
+
+	if option.ShortName != 0 {
+		data := make([]byte, utf8.RuneLen(option.ShortName))
+		utf8.EncodeRune(data, option.ShortName)
+		short = string(data)
+
+		if len(option.LongName) != 0 {
+			s = fmt.Sprintf("%s%s, %s%s",
+				string(defaultShortOptDelimiter), short,
+				defaultLongOptDelimiter, option.LongNameWithNamespace())
+		} else {
+			s = fmt.Sprintf("%s%s", string(defaultShortOptDelimiter), short)
+		}
+	} else if len(option.LongName) != 0 {
+		s = fmt.Sprintf("%s%s", defaultLongOptDelimiter, option.LongNameWithNamespace())
+	}
+
+	return s
+}
+
+// Value returns the option value as an interface{}.
+func (option *Option) Value() interface{} {
+	return option.value.Interface()
+}
+
+// Field returns the reflect struct field of the option.
+func (option *Option) Field() reflect.StructField {
+	return option.field
+}
+
+// IsSet returns true if option has been set
+func (option *Option) IsSet() bool {
+	return option.isSet
+}
+
+// IsSetDefault returns true if option has been set via the default option tag
+func (option *Option) IsSetDefault() bool {
+	return option.isSetDefault
+}
+
+// Set the value of an option to the specified value. An error will be returned
+// if the specified value could not be converted to the corresponding option
+// value type.
+func (option *Option) set(value *string) error {
+	kind := option.value.Type().Kind()
+
+	if (kind == reflect.Map || kind == reflect.Slice) && !option.isSet {
+		option.empty()
+	}
+
+	option.isSet = true
+	option.preventDefault = true
+
+	if len(option.Choices) != 0 {
+		found := false
+
+		for _, choice := range option.Choices {
+			if choice == *value {
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			allowed := strings.Join(option.Choices[0:len(option.Choices)-1], ", ")
+
+			if len(option.Choices) > 1 {
+				allowed += " or " + option.Choices[len(option.Choices)-1]
+			}
+
+			return newErrorf(ErrInvalidChoice,
+				"Invalid value `%s' for option `%s'. Allowed values are: %s",
+				*value, option, allowed)
+		}
+	}
+
+	if option.isFunc() {
+		return option.call(value)
+	} else if value != nil {
+		return convert(*value, option.value, option.tag)
+	}
+
+	return convert("", option.value, option.tag)
+}
+
+func (option *Option) canCli() bool {
+	return option.ShortName != 0 || len(option.LongName) != 0
+}
+
+func (option *Option) canArgument() bool {
+	if u := option.isUnmarshaler(); u != nil {
+		return true
+	}
+
+	return !option.isBool()
+}
+
+func (option *Option) emptyValue() reflect.Value {
+	tp := option.value.Type()
+
+	if tp.Kind() == reflect.Map {
+		return reflect.MakeMap(tp)
+	}
+
+	return reflect.Zero(tp)
+}
+
+func (option *Option) empty() {
+	if !option.isFunc() {
+		option.value.Set(option.emptyValue())
+	}
+}
+
+func (option *Option) clearDefault() {
+	usedDefault := option.Default
+
+	if envKey := option.EnvDefaultKey; envKey != "" {
+		if value, ok := os.LookupEnv(envKey); ok {
+			if option.EnvDefaultDelim != "" {
+				usedDefault = strings.Split(value,
+					option.EnvDefaultDelim)
+			} else {
+				usedDefault = []string{value}
+			}
+		}
+	}
+
+	option.isSetDefault = true
+
+	if len(usedDefault) > 0 {
+		option.empty()
+
+		for _, d := range usedDefault {
+			option.set(&d)
+			option.isSetDefault = true
+		}
+	} else {
+		tp := option.value.Type()
+
+		switch tp.Kind() {
+		case reflect.Map:
+			if option.value.IsNil() {
+				option.empty()
+			}
+		case reflect.Slice:
+			if option.value.IsNil() {
+				option.empty()
+			}
+		}
+	}
+}
+
+func (option *Option) valueIsDefault() bool {
+	// Check if the value of the option corresponds to its
+	// default value
+	emptyval := option.emptyValue()
+
+	checkvalptr := reflect.New(emptyval.Type())
+	checkval := reflect.Indirect(checkvalptr)
+
+	checkval.Set(emptyval)
+
+	if len(option.Default) != 0 {
+		for _, v := range option.Default {
+			convert(v, checkval, option.tag)
+		}
+	}
+
+	return reflect.DeepEqual(option.value.Interface(), checkval.Interface())
+}
+
+func (option *Option) isUnmarshaler() Unmarshaler {
+	v := option.value
+
+	for {
+		if !v.CanInterface() {
+			break
+		}
+
+		i := v.Interface()
+
+		if u, ok := i.(Unmarshaler); ok {
+			return u
+		}
+
+		if !v.CanAddr() {
+			break
+		}
+
+		v = v.Addr()
+	}
+
+	return nil
+}
+
+func (option *Option) isBool() bool {
+	tp := option.value.Type()
+
+	for {
+		switch tp.Kind() {
+		case reflect.Slice, reflect.Ptr:
+			tp = tp.Elem()
+		case reflect.Bool:
+			return true
+		case reflect.Func:
+			return tp.NumIn() == 0
+		default:
+			return false
+		}
+	}
+}
+
+func (option *Option) isSignedNumber() bool {
+	tp := option.value.Type()
+
+	for {
+		switch tp.Kind() {
+		case reflect.Slice, reflect.Ptr:
+			tp = tp.Elem()
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Float32, reflect.Float64:
+			return true
+		default:
+			return false
+		}
+	}
+}
+
+func (option *Option) isFunc() bool {
+	return option.value.Type().Kind() == reflect.Func
+}
+
+func (option *Option) call(value *string) error {
+	var retval []reflect.Value
+
+	if value == nil {
+		retval = option.value.Call(nil)
+	} else {
+		tp := option.value.Type().In(0)
+
+		val := reflect.New(tp)
+		val = reflect.Indirect(val)
+
+		if err := convert(*value, val, option.tag); err != nil {
+			return err
+		}
+
+		retval = option.value.Call([]reflect.Value{val})
+	}
+
+	if len(retval) == 1 && retval[0].Type() == reflect.TypeOf((*error)(nil)).Elem() {
+		if retval[0].Interface() == nil {
+			return nil
+		}
+
+		return retval[0].Interface().(error)
+	}
+
+	return nil
+}
+
+func (option *Option) updateDefaultLiteral() {
+	defs := option.Default
+	def := ""
+
+	if len(defs) == 0 && option.canArgument() {
+		var showdef bool
+
+		switch option.field.Type.Kind() {
+		case reflect.Func, reflect.Ptr:
+			showdef = !option.value.IsNil()
+		case reflect.Slice, reflect.String, reflect.Array:
+			showdef = option.value.Len() > 0
+		case reflect.Map:
+			showdef = !option.value.IsNil() && option.value.Len() > 0
+		default:
+			zeroval := reflect.Zero(option.field.Type)
+			showdef = !reflect.DeepEqual(zeroval.Interface(), option.value.Interface())
+		}
+
+		if showdef {
+			def, _ = convertToString(option.value, option.tag)
+		}
+	} else if len(defs) != 0 {
+		l := len(defs) - 1
+
+		for i := 0; i < l; i++ {
+			def += quoteIfNeeded(defs[i]) + ", "
+		}
+
+		def += quoteIfNeeded(defs[l])
+	}
+
+	option.defaultLiteral = def
+}
+
+func (option *Option) shortAndLongName() string {
+	ret := &bytes.Buffer{}
+
+	if option.ShortName != 0 {
+		ret.WriteRune(defaultShortOptDelimiter)
+		ret.WriteRune(option.ShortName)
+	}
+
+	if len(option.LongName) != 0 {
+		if option.ShortName != 0 {
+			ret.WriteRune('/')
+		}
+
+		ret.WriteString(option.LongName)
+	}
+
+	return ret.String()
+}