update vendor/

vendor/github.com/spf13/viper/README.md

@@ -15,6 +15,10 @@ Many Go projects are built using Viper including:
 
 [![Build Status](https://travis-ci.org/spf13/viper.svg)](https://travis-ci.org/spf13/viper) [![Join the chat at https://gitter.im/spf13/viper](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/spf13/viper?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) [![GoDoc](https://godoc.org/github.com/spf13/viper?status.svg)](https://godoc.org/github.com/spf13/viper)
 
+## Install
+```console
+go get -u github.com/spf13/viper
+```
 
 ## What is Viper?
 
@@ -23,7 +27,7 @@ to work within an application, and can handle all types of configuration needs
 and formats. It supports:
 
 * setting defaults
-* reading from JSON, TOML, YAML, HCL, and Java properties config files
+* reading from JSON, TOML, YAML, HCL, envfile and Java properties config files
 * live watching and re-reading of config files (optional)
 * reading from environment variables
 * reading from remote config systems (etcd or Consul), and watching changes
@@ -42,7 +46,7 @@ Viper is here to help with that.
 
 Viper does the following for you:
 
-1. Find, load, and unmarshal a configuration file in JSON, TOML, YAML, HCL, or Java properties formats.
+1. Find, load, and unmarshal a configuration file in JSON, TOML, YAML, HCL, envfile or Java properties formats.
 2. Provide a mechanism to set default values for your different
    configuration options.
 3. Provide a mechanism to set override values for options specified through
@@ -83,7 +87,7 @@ viper.SetDefault("Taxonomies", map[string]string{"tag": "tags", "category": "cat
 ### Reading Config Files
 
 Viper requires minimal configuration so it knows where to look for config files.
-Viper supports JSON, TOML, YAML, HCL, and Java Properties files. Viper can search multiple paths, but
+Viper supports JSON, TOML, YAML, HCL, envfile and Java Properties files. Viper can search multiple paths, but
 currently a single Viper instance only supports a single configuration file.
 Viper does not default to any configuration search paths leaving defaults decision
 to an application.
@@ -103,6 +107,42 @@ if err != nil { // Handle errors reading the config file
 }
 ```
 
+You can handle the specific case where no config file is found like this:
+
+```go
+if err := viper.ReadInConfig(); err != nil {
+    if _, ok := err.(viper.ConfigFileNotFoundError); ok {
+        // Config file not found; ignore error if desired
+    } else {
+        // Config file was found but another error was produced
+    }
+}
+
+// Config file found and successfully parsed
+```
+
+### Writing Config Files
+
+Reading from config files is useful, but at times you want to store all modifications made at run time.
+For that, a bunch of commands are available, each with its own purpose:
+
+* WriteConfig - writes the current viper configuration to the predefined path, if exists. Errors if no predefined path. Will overwrite the current config file, if it exists.
+* SafeWriteConfig - writes the current viper configuration to the predefined path. Errors if no predefined path. Will not overwrite the current config file, if it exists.
+* WriteConfigAs - writes the current viper configuration to the given filepath. Will overwrite the given file, if it exists.
+* SafeWriteConfigAs - writes the current viper configuration to the given filepath. Will not overwrite the given file, if it exists.
+
+As a rule of the thumb, everything marked with safe won't overwrite any file, but just create if not existent, whilst the default behavior is to create or truncate.
+
+A small examples section:
+
+```go
+viper.WriteConfig() // writes current config to predefined path set by 'viper.AddConfigPath()' and 'viper.SetConfigName'
+viper.SafeWriteConfig()
+viper.WriteConfigAs("/path/to/my/.config")
+viper.SafeWriteConfigAs("/path/to/my/.config") // will error since it has already been written
+viper.SafeWriteConfigAs("/path/to/my/.other_config")
+```
+
 ### Watching and re-reading config files
 
 Viper supports the ability to have your application live read a config file while running.
@@ -186,7 +226,7 @@ with ENV:
  * `BindEnv(string...) : error`
  * `SetEnvPrefix(string)`
  * `SetEnvKeyReplacer(string...) *strings.Replacer`
-  * `AllowEmptyEnvVar(bool)`
+ * `AllowEmptyEnv(bool)`
 
 _When working with ENV variables, it’s important to recognize that Viper
 treats ENV variables as case sensitive._
@@ -199,9 +239,9 @@ prefix.
 `BindEnv` takes one or two parameters. The first parameter is the key name, the
 second is the name of the environment variable. The name of the environment
 variable is case sensitive. If the ENV variable name is not provided, then
-Viper will automatically assume that the key name matches the ENV variable name,
-but the ENV variable is IN ALL CAPS. When you explicitly provide the ENV
-variable name, it **does not** automatically add the prefix.
+Viper will automatically assume that the ENV variable matches the following format: prefix + "_" + the key name in ALL CAPS. When you explicitly provide the ENV variable name (the second parameter),
+it **does not** automatically add the prefix. For example if the second parameter is "id",
+Viper will look for the ENV variable "ID".
 
 One important thing to recognize when working with ENV variables is that the
 value will be read each time it is accessed. Viper does not fix the value when
@@ -346,7 +386,7 @@ package:
 
 `import _ "github.com/spf13/viper/remote"`
 
-Viper will read a config string (as JSON, TOML, YAML or HCL) retrieved from a path
+Viper will read a config string (as JSON, TOML, YAML, HCL or envfile) retrieved from a path
 in a Key/Value store such as etcd or Consul.  These values take precedence over
 default values, but are overridden by configuration values retrieved from disk,
 flags, or environment variables.
@@ -381,7 +421,7 @@ how to use Consul.
 #### etcd
 ```go
 viper.AddRemoteProvider("etcd", "http://127.0.0.1:4001","/config/hugo.json")
-viper.SetConfigType("json") // because there is no file extension in a stream of bytes, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop"
+viper.SetConfigType("json") // because there is no file extension in a stream of bytes, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop", "env", "dotenv"
 err := viper.ReadRemoteConfig()
 ```
 
@@ -409,7 +449,7 @@ fmt.Println(viper.Get("hostname")) // myhostname.com
 
 ```go
 viper.AddSecureRemoteProvider("etcd","http://127.0.0.1:4001","/config/hugo.json","/etc/secrets/mykeyring.gpg")
-viper.SetConfigType("json") // because there is no file extension in a stream of bytes,  supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop"
+viper.SetConfigType("json") // because there is no file extension in a stream of bytes,  supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop", "env", "dotenv"
 err := viper.ReadRemoteConfig()
 ```
 
@@ -420,7 +460,7 @@ err := viper.ReadRemoteConfig()
 var runtime_viper = viper.New()
 
 runtime_viper.AddRemoteProvider("etcd", "http://127.0.0.1:4001", "/config/hugo.yml")
-runtime_viper.SetConfigType("yaml") // because there is no file extension in a stream of bytes, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop"
+runtime_viper.SetConfigType("yaml") // because there is no file extension in a stream of bytes, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop", "env", "dotenv"
 
 // read from remote config the first time.
 err := runtime_viper.ReadRemoteConfig()
@@ -456,6 +496,7 @@ The following functions and methods exist:
  * `GetBool(key string) : bool`
  * `GetFloat64(key string) : float64`
  * `GetInt(key string) : int`
+ * `GetIntSlice(key string) : []int`
  * `GetString(key string) : string`
  * `GetStringMap(key string) : map[string]interface{}`
  * `GetStringMapString(key string) : map[string]string`
@@ -611,15 +652,17 @@ type config struct {
 
 var C config
 
-err := Unmarshal(&C)
+err := viper.Unmarshal(&C)
 if err != nil {
 	t.Fatalf("unable to decode into struct, %v", err)
 }
 ```
 
+Viper uses [github.com/mitchellh/mapstructure](https://github.com/mitchellh/mapstructure) under the hood for unmarshaling values which uses `mapstructure` tags by default.
+
 ### Marshalling to string
 
-You may need to marhsal all the settings held in viper into a string rather than write them to a file. 
+You may need to marshal all the settings held in viper into a string rather than write them to a file. 
 You can use your favorite format's marshaller with the config returned by `AllSettings()`.
 
 ```go
@@ -630,11 +673,11 @@ import (
 
 func yamlStringSettings() string {
     c := viper.AllSettings()
-	bs, err := yaml.Marshal(c)
-	if err != nil {
-        t.Fatalf("unable to marshal config to YAML: %v", err)
+    bs, err := yaml.Marshal(c)
+    if err != nil {
+        log.Fatalf("unable to marshal config to YAML: %v", err)
     }
-	return string(bs)
+    return string(bs)
 }
 ```