Rugged for GollumRails

Adding my rugged implementation. 

works:

- [ ] page
  - [x] page creation
  - [x] page update
  - [x] page delete
  - [x] page links
- [x] file
  - [x] file create
  - [x] file delete
- [x] gollum-lib
  - [ ] all internal methods
Unused method argument - `name`. If it's necessary, use `_` or `_name` as an argument name to indicate that it won't be used. You can also write as `get_disk_reference(*)` if you want the method to accept any arguments but don't care about them.<br>Unused method argument - `commit`. If it's necessary, use `_` or `_commit` as an argument name to indicate that it won't be used. You can also write as `get_disk_reference(*)` if you want the method to accept any arguments but don't care about them.