diff --git a/vendor/go.uber.org/zap/zapcore/level.go b/vendor/go.uber.org/zap/zapcore/level.go
new file mode 100644
index 0000000..e575c9f
--- /dev/null
+++ b/vendor/go.uber.org/zap/zapcore/level.go
@@ -0,0 +1,175 @@
+// Copyright (c) 2016 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package zapcore
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+)
+
+var errUnmarshalNilLevel = errors.New("can't unmarshal a nil *Level")
+
+// A Level is a logging priority. Higher levels are more important.
+type Level int8
+
+const (
+	// DebugLevel logs are typically voluminous, and are usually disabled in
+	// production.
+	DebugLevel Level = iota - 1
+	// InfoLevel is the default logging priority.
+	InfoLevel
+	// WarnLevel logs are more important than Info, but don't need individual
+	// human review.
+	WarnLevel
+	// ErrorLevel logs are high-priority. If an application is running smoothly,
+	// it shouldn't generate any error-level logs.
+	ErrorLevel
+	// DPanicLevel logs are particularly important errors. In development the
+	// logger panics after writing the message.
+	DPanicLevel
+	// PanicLevel logs a message, then panics.
+	PanicLevel
+	// FatalLevel logs a message, then calls os.Exit(1).
+	FatalLevel
+
+	_minLevel = DebugLevel
+	_maxLevel = FatalLevel
+)
+
+// String returns a lower-case ASCII representation of the log level.
+func (l Level) String() string {
+	switch l {
+	case DebugLevel:
+		return "debug"
+	case InfoLevel:
+		return "info"
+	case WarnLevel:
+		return "warn"
+	case ErrorLevel:
+		return "error"
+	case DPanicLevel:
+		return "dpanic"
+	case PanicLevel:
+		return "panic"
+	case FatalLevel:
+		return "fatal"
+	default:
+		return fmt.Sprintf("Level(%d)", l)
+	}
+}
+
+// CapitalString returns an all-caps ASCII representation of the log level.
+func (l Level) CapitalString() string {
+	// Printing levels in all-caps is common enough that we should export this
+	// functionality.
+	switch l {
+	case DebugLevel:
+		return "DEBUG"
+	case InfoLevel:
+		return "INFO"
+	case WarnLevel:
+		return "WARN"
+	case ErrorLevel:
+		return "ERROR"
+	case DPanicLevel:
+		return "DPANIC"
+	case PanicLevel:
+		return "PANIC"
+	case FatalLevel:
+		return "FATAL"
+	default:
+		return fmt.Sprintf("LEVEL(%d)", l)
+	}
+}
+
+// MarshalText marshals the Level to text. Note that the text representation
+// drops the -Level suffix (see example).
+func (l Level) MarshalText() ([]byte, error) {
+	return []byte(l.String()), nil
+}
+
+// UnmarshalText unmarshals text to a level. Like MarshalText, UnmarshalText
+// expects the text representation of a Level to drop the -Level suffix (see
+// example).
+//
+// In particular, this makes it easy to configure logging levels using YAML,
+// TOML, or JSON files.
+func (l *Level) UnmarshalText(text []byte) error {
+	if l == nil {
+		return errUnmarshalNilLevel
+	}
+	if !l.unmarshalText(text) && !l.unmarshalText(bytes.ToLower(text)) {
+		return fmt.Errorf("unrecognized level: %q", text)
+	}
+	return nil
+}
+
+func (l *Level) unmarshalText(text []byte) bool {
+	switch string(text) {
+	case "debug", "DEBUG":
+		*l = DebugLevel
+	case "info", "INFO", "": // make the zero value useful
+		*l = InfoLevel
+	case "warn", "WARN":
+		*l = WarnLevel
+	case "error", "ERROR":
+		*l = ErrorLevel
+	case "dpanic", "DPANIC":
+		*l = DPanicLevel
+	case "panic", "PANIC":
+		*l = PanicLevel
+	case "fatal", "FATAL":
+		*l = FatalLevel
+	default:
+		return false
+	}
+	return true
+}
+
+// Set sets the level for the flag.Value interface.
+func (l *Level) Set(s string) error {
+	return l.UnmarshalText([]byte(s))
+}
+
+// Get gets the level for the flag.Getter interface.
+func (l *Level) Get() interface{} {
+	return *l
+}
+
+// Enabled returns true if the given level is at or above this level.
+func (l Level) Enabled(lvl Level) bool {
+	return lvl >= l
+}
+
+// LevelEnabler decides whether a given logging level is enabled when logging a
+// message.
+//
+// Enablers are intended to be used to implement deterministic filters;
+// concerns like sampling are better implemented as a Core.
+//
+// Each concrete Level value implements a static LevelEnabler which returns
+// true for itself and all higher logging levels. For example WarnLevel.Enabled()
+// will return true for WarnLevel, ErrorLevel, DPanicLevel, PanicLevel, and
+// FatalLevel, but return false for InfoLevel and DebugLevel.
+type LevelEnabler interface {
+	Enabled(Level) bool
+}