Loged in users can rate movies from 1 to 10

- a rating can't be deleted, only update.
- The movies have an average rating on show page.
- Added specs for Ratings (model, controller and routing).
Merge branch 'master' of github.com:EdgarOrtegaRamirez/movietracker into edgar

Conflicts:
	.gitignore
	app/models/movie.rb
	app/views/movies/show.html.haml
	db/schema.rb
	spec/models/movie_spec.rb
Added average rating field to movie

- Average rating will be re-calculated when a user creates or updates
the rating instead of calculates it when a movie is displayed.
- Fixed has_many relations on Movie and User model.
- Replaced 'radio_button_tag' for 'radio_button' (requested by
jfgomez86 on
https://github.com/jfgomez86/movietracker/pull/27#discussion_r2518256)
Merge pull request #29 from EdgarOrtegaRamirez/master

Added average rating field to Movie and Fix has_many relations
By Error in pull master