Update README.md
Always cast IDs to strings for calculations. Fixes #77

Signed-off-by: David Celis <me@davidcel.is>
Bump version to 2.1.0.2

Signed-off-by: David Celis <me@davidcel.is>
Update gemspec to include test_files

Signed-off-by: David Celis <me@davidcel.is>
Allow pagination of recommendations and users

A request made in #79 to paginate likes made me think this would be nice
for users.

```ruby
@user.recommended_movies(10, 20)
```

Signed-off-by: David Celis <me@davidcel.is>
Bump version to 2.1.1

Signed-off-by: David Celis <me@davidcel.is>
Update README.md
Add an unrate method to remove all ratings

Fixes #81

Signed-off-by: David Celis <me@davidcel.is>
Bump version to 2.1.2

Signed-off-by: David Celis <me@davidcel.is>
Update Gemfile.lock

Signed-off-by: David Celis <me@davidcel.is>
Add spec runs for multiple Rails minor versions.  Update .travis.yml to reflect this, add redis-server to services
Merge pull request #83 from petergoldstein/feature/multi_rails_specs_and_travis

Multiple Rails versions in specs, update Travis, add JRuby to specs
Support subclassing ratables

This allows ratable classes to have subclasses that properly accumulate ratings
in the same ratable category.
Clean up Redis keys a bit

Rename a few things, add comments, and factor out some other bits relating
to Redis key mapping.
Merge pull request #84 from aaronroyer/subclassable_ratables

Subclassable ratables
Ratable top method now accepts a start argument to be able to paginate top elements
ratable top method options is now a Hash
Merge pull request #85 from StudioMelipone/ratable-top-start

Ratable top method now accepts a start argument
Remove 1.8.7 from Travis, add 2.1.0

Signed-off-by: David Celis <me@davidcel.is>
Add 1.8 hash syntax back. I don't want a major version bump yet.

Signed-off-by: David Celis <me@davidcel.is>