first draft of atheme migration code

vendor/github.com/GehirnInc/crypt/README.rst

@@ -0,0 +1,61 @@
+.. image:: https://travis-ci.org/GehirnInc/crypt.svg?branch=master
+    :target: https://travis-ci.org/GehirnInc/crypt
+
+crypt - A password hashing library for Go
+=========================================
+crypt provides pure golang implementations of UNIX's crypt(3).
+
+The goal of crypt is to bring a library of many common and popular password
+hashing algorithms to Go and to provide a simple and consistent interface to
+each of them. As every hashing method is implemented in pure Go, this library
+should be as portable as Go itself.
+
+All hashing methods come with a test suite which verifies their operation
+against itself as well as the output of other password hashing implementations
+to ensure compatibility with them.
+
+I hope you find this library to be useful and easy to use!
+
+Install
+-------
+
+To install crypt, use the *go get* command.
+
+.. code-block:: sh
+
+   go get github.com/GehirnInc/crypt
+
+
+Usage
+-----
+
+.. code-block:: go
+
+    package main
+
+    import (
+    	"fmt"
+
+    	"github.com/GehirnInc/crypt"
+    	_ "github.com/GehirnInc/crypt/sha256_crypt"
+    )
+
+    func main() {
+    	crypt := crypt.SHA256.New()
+    	ret, _ := crypt.Generate([]byte("secret"), []byte("$5$salt"))
+    	fmt.Println(ret)
+
+    	err := crypt.Verify(ret, []byte("secret"))
+    	fmt.Println(err)
+
+    	// Output:
+    	// $5$salt$kpa26zwgX83BPSR8d7w93OIXbFt/d3UOTZaAu5vsTM6
+    	// <nil>
+    }
+
+Documentation
+-------------
+
+The documentation is available on GoDoc_.
+
+.. _GoDoc: https://godoc.org/github.com/GehirnInc/crypt