Add instructions for installing from Github

Author: felixge

Readme.md

@@ -11,6 +11,13 @@ npm install [email protected]
 Despite the alpha tag, this is the recommended version for new applications.
 For information about the previous 0.9.x releases, visit the [v0.9 branch][].
 
+Sometimes I may also ask you to install the latest version from Github to check
+if a bugfix is working. In this case, please do:
+
+```
+npm install git://github.com/felixge/node-mysql.git
+```
+
 [v0.9 branch]: https://github.com/felixge/node-mysql/tree/v0.9
 
 ## Introduction