diff --git a/vendor/golang.org/x/text/language/tags.go b/vendor/golang.org/x/text/language/tags.go
new file mode 100644
index 0000000..de30155
--- /dev/null
+++ b/vendor/golang.org/x/text/language/tags.go
@@ -0,0 +1,143 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package language
+
+// TODO: Various sets of commonly use tags and regions.
+
+// MustParse is like Parse, but panics if the given BCP 47 tag cannot be parsed.
+// It simplifies safe initialization of Tag values.
+func MustParse(s string) Tag {
+	t, err := Parse(s)
+	if err != nil {
+		panic(err)
+	}
+	return t
+}
+
+// MustParse is like Parse, but panics if the given BCP 47 tag cannot be parsed.
+// It simplifies safe initialization of Tag values.
+func (c CanonType) MustParse(s string) Tag {
+	t, err := c.Parse(s)
+	if err != nil {
+		panic(err)
+	}
+	return t
+}
+
+// MustParseBase is like ParseBase, but panics if the given base cannot be parsed.
+// It simplifies safe initialization of Base values.
+func MustParseBase(s string) Base {
+	b, err := ParseBase(s)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}
+
+// MustParseScript is like ParseScript, but panics if the given script cannot be
+// parsed. It simplifies safe initialization of Script values.
+func MustParseScript(s string) Script {
+	scr, err := ParseScript(s)
+	if err != nil {
+		panic(err)
+	}
+	return scr
+}
+
+// MustParseRegion is like ParseRegion, but panics if the given region cannot be
+// parsed. It simplifies safe initialization of Region values.
+func MustParseRegion(s string) Region {
+	r, err := ParseRegion(s)
+	if err != nil {
+		panic(err)
+	}
+	return r
+}
+
+var (
+	und = Tag{}
+
+	Und Tag = Tag{}
+
+	Afrikaans            Tag = Tag{lang: _af}                //  af
+	Amharic              Tag = Tag{lang: _am}                //  am
+	Arabic               Tag = Tag{lang: _ar}                //  ar
+	ModernStandardArabic Tag = Tag{lang: _ar, region: _001}  //  ar-001
+	Azerbaijani          Tag = Tag{lang: _az}                //  az
+	Bulgarian            Tag = Tag{lang: _bg}                //  bg
+	Bengali              Tag = Tag{lang: _bn}                //  bn
+	Catalan              Tag = Tag{lang: _ca}                //  ca
+	Czech                Tag = Tag{lang: _cs}                //  cs
+	Danish               Tag = Tag{lang: _da}                //  da
+	German               Tag = Tag{lang: _de}                //  de
+	Greek                Tag = Tag{lang: _el}                //  el
+	English              Tag = Tag{lang: _en}                //  en
+	AmericanEnglish      Tag = Tag{lang: _en, region: _US}   //  en-US
+	BritishEnglish       Tag = Tag{lang: _en, region: _GB}   //  en-GB
+	Spanish              Tag = Tag{lang: _es}                //  es
+	EuropeanSpanish      Tag = Tag{lang: _es, region: _ES}   //  es-ES
+	LatinAmericanSpanish Tag = Tag{lang: _es, region: _419}  //  es-419
+	Estonian             Tag = Tag{lang: _et}                //  et
+	Persian              Tag = Tag{lang: _fa}                //  fa
+	Finnish              Tag = Tag{lang: _fi}                //  fi
+	Filipino             Tag = Tag{lang: _fil}               //  fil
+	French               Tag = Tag{lang: _fr}                //  fr
+	CanadianFrench       Tag = Tag{lang: _fr, region: _CA}   //  fr-CA
+	Gujarati             Tag = Tag{lang: _gu}                //  gu
+	Hebrew               Tag = Tag{lang: _he}                //  he
+	Hindi                Tag = Tag{lang: _hi}                //  hi
+	Croatian             Tag = Tag{lang: _hr}                //  hr
+	Hungarian            Tag = Tag{lang: _hu}                //  hu
+	Armenian             Tag = Tag{lang: _hy}                //  hy
+	Indonesian           Tag = Tag{lang: _id}                //  id
+	Icelandic            Tag = Tag{lang: _is}                //  is
+	Italian              Tag = Tag{lang: _it}                //  it
+	Japanese             Tag = Tag{lang: _ja}                //  ja
+	Georgian             Tag = Tag{lang: _ka}                //  ka
+	Kazakh               Tag = Tag{lang: _kk}                //  kk
+	Khmer                Tag = Tag{lang: _km}                //  km
+	Kannada              Tag = Tag{lang: _kn}                //  kn
+	Korean               Tag = Tag{lang: _ko}                //  ko
+	Kirghiz              Tag = Tag{lang: _ky}                //  ky
+	Lao                  Tag = Tag{lang: _lo}                //  lo
+	Lithuanian           Tag = Tag{lang: _lt}                //  lt
+	Latvian              Tag = Tag{lang: _lv}                //  lv
+	Macedonian           Tag = Tag{lang: _mk}                //  mk
+	Malayalam            Tag = Tag{lang: _ml}                //  ml
+	Mongolian            Tag = Tag{lang: _mn}                //  mn
+	Marathi              Tag = Tag{lang: _mr}                //  mr
+	Malay                Tag = Tag{lang: _ms}                //  ms
+	Burmese              Tag = Tag{lang: _my}                //  my
+	Nepali               Tag = Tag{lang: _ne}                //  ne
+	Dutch                Tag = Tag{lang: _nl}                //  nl
+	Norwegian            Tag = Tag{lang: _no}                //  no
+	Punjabi              Tag = Tag{lang: _pa}                //  pa
+	Polish               Tag = Tag{lang: _pl}                //  pl
+	Portuguese           Tag = Tag{lang: _pt}                //  pt
+	BrazilianPortuguese  Tag = Tag{lang: _pt, region: _BR}   //  pt-BR
+	EuropeanPortuguese   Tag = Tag{lang: _pt, region: _PT}   //  pt-PT
+	Romanian             Tag = Tag{lang: _ro}                //  ro
+	Russian              Tag = Tag{lang: _ru}                //  ru
+	Sinhala              Tag = Tag{lang: _si}                //  si
+	Slovak               Tag = Tag{lang: _sk}                //  sk
+	Slovenian            Tag = Tag{lang: _sl}                //  sl
+	Albanian             Tag = Tag{lang: _sq}                //  sq
+	Serbian              Tag = Tag{lang: _sr}                //  sr
+	SerbianLatin         Tag = Tag{lang: _sr, script: _Latn} //  sr-Latn
+	Swedish              Tag = Tag{lang: _sv}                //  sv
+	Swahili              Tag = Tag{lang: _sw}                //  sw
+	Tamil                Tag = Tag{lang: _ta}                //  ta
+	Telugu               Tag = Tag{lang: _te}                //  te
+	Thai                 Tag = Tag{lang: _th}                //  th
+	Turkish              Tag = Tag{lang: _tr}                //  tr
+	Ukrainian            Tag = Tag{lang: _uk}                //  uk
+	Urdu                 Tag = Tag{lang: _ur}                //  ur
+	Uzbek                Tag = Tag{lang: _uz}                //  uz
+	Vietnamese           Tag = Tag{lang: _vi}                //  vi
+	Chinese              Tag = Tag{lang: _zh}                //  zh
+	SimplifiedChinese    Tag = Tag{lang: _zh, script: _Hans} //  zh-Hans
+	TraditionalChinese   Tag = Tag{lang: _zh, script: _Hant} //  zh-Hant
+	Zulu                 Tag = Tag{lang: _zu}                //  zu
+)