make contributors a list

Author: schworer

README.md

@@ -51,5 +51,5 @@ Install `httplib2` with `pip` or `easy_install`.
 **Note:** If you set the `ZENCODER_API_KEY` environment variable to your api key, you don't have to provide it when initializing Zencoder.
 
 ## Contributors
-    Senko Rasic [github](http://github.com/senko)
+ * Senko Rasic [github](http://github.com/senko)