Switch gitter adapter for hubot-gitter2

Ivan you might want to try this adapter instead of hubot-gitter. I don't know what the starting script looks like but heres the link for the hubot-gitter2 repo.

https://github.com/huafu/hubot-gitter2

To start the bot using the gitter2 adapter: `HUBOT_GITTER2_TOKEN=<your token> ./bin/hubot -a gutter -n <your name>`