(TODO : Create a gem).

- Order user, tag, channel by their size.

- Pagination
- Database reworking
- Using of rake migration and seed

 - Tags weren't displayed. Solution : composite_primary_keys gem to manage the shi*** database design.
 - Json unreadable. Solution : active_model_serializers to select json fields.
 - SQL requests too slow. Solution : includes in place of joins (3x faster).
 PS : TY Zar.

- Few CSS updates and bugfixes.

- Expanded player with a better integration,
- To finish : Autoplay goes to the next page.

- Now all integrated  players (iframe) are in javascript.
- Autonext track is on.

Youtube player autonext track is OOOONNNNNN -- The player is handled by javascript now (ruby before).