Gem source:
https://github.com/ryanto/acts_as_votable
Source code:
https://github.com/corsego/16-acts_as_votable

Blogpost - install gem:
https://blog.corsego.com/gem-acts-as-votable
Blogpost - best ajax voting:
https://blog.corsego.com/gem-acts-as-votable-2

0:00 Intro
1:08 gem acts_as_votable
4:10 upvote, unvote posts
14:30 summary
15:34 see votes count
20:26 sort posts by rating
20:57 summary of adding votes count
21:40 downvote posts
24:10 final demo