coding_18845_edit_comment

- [x] Coding functions
    - [x] create fucntion put_update_comment  - (in controller)
    - [x] create function update_comment($data) - (in model)
- [x] unit testing
    - [x] create function update_comment_ok (controller)
    - [x] create function update_comment_notok( controller)
    - [x] create function update_comment_empty( controller)
    - [x] create function update_comment_ok (model)
    - [x] create function update_comment_notok( model)
    - [x] create function update_comment_empty( model)