DO NOT MERGE: initial commit of forum related roles

works from scratch on gce and better generalization

missed file

changing user for checkout task

reverting path change

fix typo

fully working on debian

working upstart

moving env from bashrc

removing unused template

adding template for ruby env setting

removing unused template

removing forum and ruby env from bashrc, general cleanup


--------


Run with a playbook like follows:

```
    - common
    - mongo
    - oraclejdk
    - elasticsearch
    - { role: 'rbenv', rbenv_user: 'forum', rbenv_user_home: '/opt/forum', rbenv_ruby_version: '1.9.3-p448' }
    - forum
```