Fix README install instructions

Author: albfan

README

@@ -0,0 +1,18 @@
+# vim-ref addon for gtkdoc (or devhelp)
+
+See gtk documentation on vim
+
+## Install with Vundle:
+
+    Plugin 'thinca/vim-ref'
+    Plugin 'eiiches/gtkdoc'
+
+## Usage:
+
+    :Ref gtkdoc <keyword>
+	 
+## Credits
+
+	- gtkdoc-cui [http://github.com/eiiches/gtkdoc]
+	- vim-ref [http://github.com/thinca/vim-ref]
+