diff --git a/vendor/golang.org/x/text/collate/option.go b/vendor/golang.org/x/text/collate/option.go
new file mode 100644
index 0000000..19cb546
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/option.go
@@ -0,0 +1,239 @@
+// Copyright 2014 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 collate
+
+import (
+	"sort"
+
+	"golang.org/x/text/internal/colltab"
+	"golang.org/x/text/language"
+	"golang.org/x/text/unicode/norm"
+)
+
+// newCollator creates a new collator with default options configured.
+func newCollator(t colltab.Weighter) *Collator {
+	// Initialize a collator with default options.
+	c := &Collator{
+		options: options{
+			ignore: [colltab.NumLevels]bool{
+				colltab.Quaternary: true,
+				colltab.Identity:   true,
+			},
+			f: norm.NFD,
+			t: t,
+		},
+	}
+
+	// TODO: store vt in tags or remove.
+	c.variableTop = t.Top()
+
+	return c
+}
+
+// An Option is used to change the behavior of a Collator. Options override the
+// settings passed through the locale identifier.
+type Option struct {
+	priority int
+	f        func(o *options)
+}
+
+type prioritizedOptions []Option
+
+func (p prioritizedOptions) Len() int {
+	return len(p)
+}
+
+func (p prioritizedOptions) Swap(i, j int) {
+	p[i], p[j] = p[j], p[i]
+}
+
+func (p prioritizedOptions) Less(i, j int) bool {
+	return p[i].priority < p[j].priority
+}
+
+type options struct {
+	// ignore specifies which levels to ignore.
+	ignore [colltab.NumLevels]bool
+
+	// caseLevel is true if there is an additional level of case matching
+	// between the secondary and tertiary levels.
+	caseLevel bool
+
+	// backwards specifies the order of sorting at the secondary level.
+	// This option exists predominantly to support reverse sorting of accents in French.
+	backwards bool
+
+	// numeric specifies whether any sequence of decimal digits (category is Nd)
+	// is sorted at a primary level with its numeric value.
+	// For example, "A-21" < "A-123".
+	// This option is set by wrapping the main Weighter with NewNumericWeighter.
+	numeric bool
+
+	// alternate specifies an alternative handling of variables.
+	alternate alternateHandling
+
+	// variableTop is the largest primary value that is considered to be
+	// variable.
+	variableTop uint32
+
+	t colltab.Weighter
+
+	f norm.Form
+}
+
+func (o *options) setOptions(opts []Option) {
+	sort.Sort(prioritizedOptions(opts))
+	for _, x := range opts {
+		x.f(o)
+	}
+}
+
+// OptionsFromTag extracts the BCP47 collation options from the tag and
+// configures a collator accordingly. These options are set before any other
+// option.
+func OptionsFromTag(t language.Tag) Option {
+	return Option{0, func(o *options) {
+		o.setFromTag(t)
+	}}
+}
+
+func (o *options) setFromTag(t language.Tag) {
+	o.caseLevel = ldmlBool(t, o.caseLevel, "kc")
+	o.backwards = ldmlBool(t, o.backwards, "kb")
+	o.numeric = ldmlBool(t, o.numeric, "kn")
+
+	// Extract settings from the BCP47 u extension.
+	switch t.TypeForKey("ks") { // strength
+	case "level1":
+		o.ignore[colltab.Secondary] = true
+		o.ignore[colltab.Tertiary] = true
+	case "level2":
+		o.ignore[colltab.Tertiary] = true
+	case "level3", "":
+		// The default.
+	case "level4":
+		o.ignore[colltab.Quaternary] = false
+	case "identic":
+		o.ignore[colltab.Quaternary] = false
+		o.ignore[colltab.Identity] = false
+	}
+
+	switch t.TypeForKey("ka") {
+	case "shifted":
+		o.alternate = altShifted
+	// The following two types are not official BCP47, but we support them to
+	// give access to this otherwise hidden functionality. The name blanked is
+	// derived from the LDML name blanked and posix reflects the main use of
+	// the shift-trimmed option.
+	case "blanked":
+		o.alternate = altBlanked
+	case "posix":
+		o.alternate = altShiftTrimmed
+	}
+
+	// TODO: caseFirst ("kf"), reorder ("kr"), and maybe variableTop ("vt").
+
+	// Not used:
+	// - normalization ("kk", not necessary for this implementation)
+	// - hiraganaQuatenary ("kh", obsolete)
+}
+
+func ldmlBool(t language.Tag, old bool, key string) bool {
+	switch t.TypeForKey(key) {
+	case "true":
+		return true
+	case "false":
+		return false
+	default:
+		return old
+	}
+}
+
+var (
+	// IgnoreCase sets case-insensitive comparison.
+	IgnoreCase Option = ignoreCase
+	ignoreCase        = Option{3, ignoreCaseF}
+
+	// IgnoreDiacritics causes diacritical marks to be ignored. ("o" == "ö").
+	IgnoreDiacritics Option = ignoreDiacritics
+	ignoreDiacritics        = Option{3, ignoreDiacriticsF}
+
+	// IgnoreWidth causes full-width characters to match their half-width
+	// equivalents.
+	IgnoreWidth Option = ignoreWidth
+	ignoreWidth        = Option{2, ignoreWidthF}
+
+	// Loose sets the collator to ignore diacritics, case and width.
+	Loose Option = loose
+	loose        = Option{4, looseF}
+
+	// Force ordering if strings are equivalent but not equal.
+	Force Option = force
+	force        = Option{5, forceF}
+
+	// Numeric specifies that numbers should sort numerically ("2" < "12").
+	Numeric Option = numeric
+	numeric        = Option{5, numericF}
+)
+
+func ignoreWidthF(o *options) {
+	o.ignore[colltab.Tertiary] = true
+	o.caseLevel = true
+}
+
+func ignoreDiacriticsF(o *options) {
+	o.ignore[colltab.Secondary] = true
+}
+
+func ignoreCaseF(o *options) {
+	o.ignore[colltab.Tertiary] = true
+	o.caseLevel = false
+}
+
+func looseF(o *options) {
+	ignoreWidthF(o)
+	ignoreDiacriticsF(o)
+	ignoreCaseF(o)
+}
+
+func forceF(o *options) {
+	o.ignore[colltab.Identity] = false
+}
+
+func numericF(o *options) { o.numeric = true }
+
+// Reorder overrides the pre-defined ordering of scripts and character sets.
+func Reorder(s ...string) Option {
+	// TODO: need fractional weights to implement this.
+	panic("TODO: implement")
+}
+
+// TODO: consider making these public again. These options cannot be fully
+// specified in BCP47, so an API interface seems warranted. Still a higher-level
+// interface would be nice (e.g. a POSIX option for enabling altShiftTrimmed)
+
+// alternateHandling identifies the various ways in which variables are handled.
+// A rune with a primary weight lower than the variable top is considered a
+// variable.
+// See https://www.unicode.org/reports/tr10/#Variable_Weighting for details.
+type alternateHandling int
+
+const (
+	// altNonIgnorable turns off special handling of variables.
+	altNonIgnorable alternateHandling = iota
+
+	// altBlanked sets variables and all subsequent primary ignorables to be
+	// ignorable at all levels. This is identical to removing all variables
+	// and subsequent primary ignorables from the input.
+	altBlanked
+
+	// altShifted sets variables to be ignorable for levels one through three and
+	// adds a fourth level based on the values of the ignored levels.
+	altShifted
+
+	// altShiftTrimmed is a slight variant of altShifted that is used to
+	// emulate POSIX.
+	altShiftTrimmed
+)