Revolution (gemify, add config yml)

- Gemify

  - This is useful for separate repository by deploy scripts and application itself

    ```
(in my deployment repository)
├── Capfile
├── Gemfile
├── Gemfile.lock
├── config
│   └── deploy.rb
└── start.sh
    ```

- Add retrobot.yml for configuration via file

  - ENV is insecure sometime, not useful in all situations

- some refactors

--

I'll add some additional features after this get merged

--

I left `dotenv` for compatibility, removing dotenv is up to you.