diff --git a/vendor/github.com/jessevdk/go-flags/group.go b/vendor/github.com/jessevdk/go-flags/group.go
new file mode 100644
index 0000000..9e057ab
--- /dev/null
+++ b/vendor/github.com/jessevdk/go-flags/group.go
@@ -0,0 +1,406 @@
+// Copyright 2012 Jesse van den Kieboom. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package flags
+
+import (
+	"errors"
+	"reflect"
+	"strings"
+	"unicode/utf8"
+)
+
+// ErrNotPointerToStruct indicates that a provided data container is not
+// a pointer to a struct. Only pointers to structs are valid data containers
+// for options.
+var ErrNotPointerToStruct = errors.New("provided data is not a pointer to struct")
+
+// Group represents an option group. Option groups can be used to logically
+// group options together under a description. Groups are only used to provide
+// more structure to options both for the user (as displayed in the help message)
+// and for you, since groups can be nested.
+type Group struct {
+	// A short description of the group. The
+	// short description is primarily used in the built-in generated help
+	// message
+	ShortDescription string
+
+	// A long description of the group. The long
+	// description is primarily used to present information on commands
+	// (Command embeds Group) in the built-in generated help and man pages.
+	LongDescription string
+
+	// The namespace of the group
+	Namespace string
+
+	// If true, the group is not displayed in the help or man page
+	Hidden bool
+
+	// The parent of the group or nil if it has no parent
+	parent interface{}
+
+	// All the options in the group
+	options []*Option
+
+	// All the subgroups
+	groups []*Group
+
+	// Whether the group represents the built-in help group
+	isBuiltinHelp bool
+
+	data interface{}
+}
+
+type scanHandler func(reflect.Value, *reflect.StructField) (bool, error)
+
+// AddGroup adds a new group to the command with the given name and data. The
+// data needs to be a pointer to a struct from which the fields indicate which
+// options are in the group.
+func (g *Group) AddGroup(shortDescription string, longDescription string, data interface{}) (*Group, error) {
+	group := newGroup(shortDescription, longDescription, data)
+
+	group.parent = g
+
+	if err := group.scan(); err != nil {
+		return nil, err
+	}
+
+	g.groups = append(g.groups, group)
+	return group, nil
+}
+
+// Groups returns the list of groups embedded in this group.
+func (g *Group) Groups() []*Group {
+	return g.groups
+}
+
+// Options returns the list of options in this group.
+func (g *Group) Options() []*Option {
+	return g.options
+}
+
+// Find locates the subgroup with the given short description and returns it.
+// If no such group can be found Find will return nil. Note that the description
+// is matched case insensitively.
+func (g *Group) Find(shortDescription string) *Group {
+	lshortDescription := strings.ToLower(shortDescription)
+
+	var ret *Group
+
+	g.eachGroup(func(gg *Group) {
+		if gg != g && strings.ToLower(gg.ShortDescription) == lshortDescription {
+			ret = gg
+		}
+	})
+
+	return ret
+}
+
+func (g *Group) findOption(matcher func(*Option) bool) (option *Option) {
+	g.eachGroup(func(g *Group) {
+		for _, opt := range g.options {
+			if option == nil && matcher(opt) {
+				option = opt
+			}
+		}
+	})
+
+	return option
+}
+
+// FindOptionByLongName finds an option that is part of the group, or any of its
+// subgroups, by matching its long name (including the option namespace).
+func (g *Group) FindOptionByLongName(longName string) *Option {
+	return g.findOption(func(option *Option) bool {
+		return option.LongNameWithNamespace() == longName
+	})
+}
+
+// FindOptionByShortName finds an option that is part of the group, or any of
+// its subgroups, by matching its short name.
+func (g *Group) FindOptionByShortName(shortName rune) *Option {
+	return g.findOption(func(option *Option) bool {
+		return option.ShortName == shortName
+	})
+}
+
+func newGroup(shortDescription string, longDescription string, data interface{}) *Group {
+	return &Group{
+		ShortDescription: shortDescription,
+		LongDescription:  longDescription,
+
+		data: data,
+	}
+}
+
+func (g *Group) optionByName(name string, namematch func(*Option, string) bool) *Option {
+	prio := 0
+	var retopt *Option
+
+	g.eachGroup(func(g *Group) {
+		for _, opt := range g.options {
+			if namematch != nil && namematch(opt, name) && prio < 4 {
+				retopt = opt
+				prio = 4
+			}
+
+			if name == opt.field.Name && prio < 3 {
+				retopt = opt
+				prio = 3
+			}
+
+			if name == opt.LongNameWithNamespace() && prio < 2 {
+				retopt = opt
+				prio = 2
+			}
+
+			if opt.ShortName != 0 && name == string(opt.ShortName) && prio < 1 {
+				retopt = opt
+				prio = 1
+			}
+		}
+	})
+
+	return retopt
+}
+
+func (g *Group) eachGroup(f func(*Group)) {
+	f(g)
+
+	for _, gg := range g.groups {
+		gg.eachGroup(f)
+	}
+}
+
+func isStringFalsy(s string) bool {
+	return s == "" || s == "false" || s == "no" || s == "0"
+}
+
+func (g *Group) scanStruct(realval reflect.Value, sfield *reflect.StructField, handler scanHandler) error {
+	stype := realval.Type()
+
+	if sfield != nil {
+		if ok, err := handler(realval, sfield); err != nil {
+			return err
+		} else if ok {
+			return nil
+		}
+	}
+
+	for i := 0; i < stype.NumField(); i++ {
+		field := stype.Field(i)
+
+		// PkgName is set only for non-exported fields, which we ignore
+		if field.PkgPath != "" && !field.Anonymous {
+			continue
+		}
+
+		mtag := newMultiTag(string(field.Tag))
+
+		if err := mtag.Parse(); err != nil {
+			return err
+		}
+
+		// Skip fields with the no-flag tag
+		if mtag.Get("no-flag") != "" {
+			continue
+		}
+
+		// Dive deep into structs or pointers to structs
+		kind := field.Type.Kind()
+		fld := realval.Field(i)
+
+		if kind == reflect.Struct {
+			if err := g.scanStruct(fld, &field, handler); err != nil {
+				return err
+			}
+		} else if kind == reflect.Ptr && field.Type.Elem().Kind() == reflect.Struct {
+			flagCountBefore := len(g.options) + len(g.groups)
+
+			if fld.IsNil() {
+				fld = reflect.New(fld.Type().Elem())
+			}
+
+			if err := g.scanStruct(reflect.Indirect(fld), &field, handler); err != nil {
+				return err
+			}
+
+			if len(g.options)+len(g.groups) != flagCountBefore {
+				realval.Field(i).Set(fld)
+			}
+		}
+
+		longname := mtag.Get("long")
+		shortname := mtag.Get("short")
+
+		// Need at least either a short or long name
+		if longname == "" && shortname == "" && mtag.Get("ini-name") == "" {
+			continue
+		}
+
+		short := rune(0)
+		rc := utf8.RuneCountInString(shortname)
+
+		if rc > 1 {
+			return newErrorf(ErrShortNameTooLong,
+				"short names can only be 1 character long, not `%s'",
+				shortname)
+
+		} else if rc == 1 {
+			short, _ = utf8.DecodeRuneInString(shortname)
+		}
+
+		description := mtag.Get("description")
+		def := mtag.GetMany("default")
+
+		optionalValue := mtag.GetMany("optional-value")
+		valueName := mtag.Get("value-name")
+		defaultMask := mtag.Get("default-mask")
+
+		optional := !isStringFalsy(mtag.Get("optional"))
+		required := !isStringFalsy(mtag.Get("required"))
+		choices := mtag.GetMany("choice")
+		hidden := !isStringFalsy(mtag.Get("hidden"))
+
+		option := &Option{
+			Description:      description,
+			ShortName:        short,
+			LongName:         longname,
+			Default:          def,
+			EnvDefaultKey:    mtag.Get("env"),
+			EnvDefaultDelim:  mtag.Get("env-delim"),
+			OptionalArgument: optional,
+			OptionalValue:    optionalValue,
+			Required:         required,
+			ValueName:        valueName,
+			DefaultMask:      defaultMask,
+			Choices:          choices,
+			Hidden:           hidden,
+
+			group: g,
+
+			field: field,
+			value: realval.Field(i),
+			tag:   mtag,
+		}
+
+		if option.isBool() && option.Default != nil {
+			return newErrorf(ErrInvalidTag,
+				"boolean flag `%s' may not have default values, they always default to `false' and can only be turned on",
+				option.shortAndLongName())
+		}
+
+		g.options = append(g.options, option)
+	}
+
+	return nil
+}
+
+func (g *Group) checkForDuplicateFlags() *Error {
+	shortNames := make(map[rune]*Option)
+	longNames := make(map[string]*Option)
+
+	var duplicateError *Error
+
+	g.eachGroup(func(g *Group) {
+		for _, option := range g.options {
+			if option.LongName != "" {
+				longName := option.LongNameWithNamespace()
+
+				if otherOption, ok := longNames[longName]; ok {
+					duplicateError = newErrorf(ErrDuplicatedFlag, "option `%s' uses the same long name as option `%s'", option, otherOption)
+					return
+				}
+				longNames[longName] = option
+			}
+			if option.ShortName != 0 {
+				if otherOption, ok := shortNames[option.ShortName]; ok {
+					duplicateError = newErrorf(ErrDuplicatedFlag, "option `%s' uses the same short name as option `%s'", option, otherOption)
+					return
+				}
+				shortNames[option.ShortName] = option
+			}
+		}
+	})
+
+	return duplicateError
+}
+
+func (g *Group) scanSubGroupHandler(realval reflect.Value, sfield *reflect.StructField) (bool, error) {
+	mtag := newMultiTag(string(sfield.Tag))
+
+	if err := mtag.Parse(); err != nil {
+		return true, err
+	}
+
+	subgroup := mtag.Get("group")
+
+	if len(subgroup) != 0 {
+		var ptrval reflect.Value
+
+		if realval.Kind() == reflect.Ptr {
+			ptrval = realval
+
+			if ptrval.IsNil() {
+				ptrval.Set(reflect.New(ptrval.Type()))
+			}
+		} else {
+			ptrval = realval.Addr()
+		}
+
+		description := mtag.Get("description")
+
+		group, err := g.AddGroup(subgroup, description, ptrval.Interface())
+
+		if err != nil {
+			return true, err
+		}
+
+		group.Namespace = mtag.Get("namespace")
+		group.Hidden = mtag.Get("hidden") != ""
+
+		return true, nil
+	}
+
+	return false, nil
+}
+
+func (g *Group) scanType(handler scanHandler) error {
+	// Get all the public fields in the data struct
+	ptrval := reflect.ValueOf(g.data)
+
+	if ptrval.Type().Kind() != reflect.Ptr {
+		panic(ErrNotPointerToStruct)
+	}
+
+	stype := ptrval.Type().Elem()
+
+	if stype.Kind() != reflect.Struct {
+		panic(ErrNotPointerToStruct)
+	}
+
+	realval := reflect.Indirect(ptrval)
+
+	if err := g.scanStruct(realval, nil, handler); err != nil {
+		return err
+	}
+
+	if err := g.checkForDuplicateFlags(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (g *Group) scan() error {
+	return g.scanType(g.scanSubGroupHandler)
+}
+
+func (g *Group) groupByName(name string) *Group {
+	if len(name) == 0 {
+		return g
+	}
+
+	return g.Find(name)
+}