1. downlod erlang snippets.
http://www.joeandmotorboat.com/files/snippets-archive.tar.gz
unzip it, the unziped filename is erlang.xml
2. in gedit, select [edit->preference->plugins->snippets]
3. depress [configure plugin] button.
4. in the opened window, select erlang in left box, then press the [create snippets] button.
5. paste the erlang.xml contents to textbox right side.
6. ok!