refactor: openpitrix module

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/koding/multiconfig/README.md

@@ -0,0 +1,92 @@
+# Multiconfig [![GoDoc](https://godoc.org/github.com/koding/multiconfig?status.svg)](http://godoc.org/github.com/koding/multiconfig) [![Build Status](https://travis-ci.org/koding/multiconfig.svg?branch=master)](https://travis-ci.org/koding/multiconfig)
+
+Load configuration from multiple sources. Multiconfig makes loading/parsing
+from different configuration sources an easy task. The problem with any app is
+that with time there are many options how to populate a set of configs.
+Multiconfig makes it easy by dynamically creating all necessary options.
+Checkout the example below to see it in action.
+
+## Features
+
+Multiconfig is able to read configuration automatically based on the given struct's field names from the following sources:
+
+* Struct tags
+* TOML file
+* JSON file
+* YAML file
+* Environment variables
+* Flags
+
+
+## Install
+
+```bash
+go get github.com/koding/multiconfig
+```
+
+## Usage and Examples
+
+Lets define and struct that defines our configuration
+
+```go
+type Server struct {
+	Name    string `required:"true"`
+	Port    int    `default:"6060"`
+	Enabled bool
+	Users   []string
+}
+```
+
+Load the configuration into multiconfig:
+
+```go
+// Create a new DefaultLoader without or with an initial config file
+m := multiconfig.New()
+m := multiconfig.NewWithPath("config.toml") // supports TOML, JSON and YAML
+
+// Get an empty struct for your configuration
+serverConf := new(Server)
+
+// Populated the serverConf struct
+err := m.Load(serverConf) // Check for error
+m.MustLoad(serverConf)    // Panic's if there is any error
+
+// Access now populated fields
+serverConf.Port // by default 6060
+serverConf.Name // "koding"
+```
+
+Run your app:
+
+```sh
+# Sets default values first which are defined in each field tag value. 
+# Starts to load from config.toml
+$ app
+
+# Override any config easily with environment variables, environment variables
+# are automatically generated in the form of STRUCTNAME_FIELDNAME
+$ SERVER_PORT=4000 SERVER_NAME="koding" app
+
+# Or pass via flag. Flags are also automatically generated based on the field
+# name
+$ app -port 4000 -users "gopher,koding"
+
+# Print dynamically generated flags and environment variables:
+$ app -help
+Usage of app:
+  -enabled=true: Change value of Enabled.
+  -name=Koding: Change value of Name.
+  -port=6060: Change value of Port.
+  -users=[ankara istanbul]: Change value of Users.
+
+Generated environment variables:
+   SERVER_NAME
+   SERVER_PORT
+   SERVER_ENABLED
+   SERVER_USERS
+```
+
+
+## License
+
+The MIT License (MIT) - see [LICENSE](/LICENSE) for more details