Add rubocop

[ddecollo]

Fixes #30

[ajkiessl]

Looks great! Thanks for doing this; it'll help keep things clean moving forward. One thing I noticed in the rubocop output is this message:

Tip: Based on detected gems, the following RuboCop extension libraries might be helpful:

• rubocop-rails (https://rubygems.org/gems/rubocop-rails)
• rubocop-rspec (https://rubygems.org/gems/rubocop-rspec)

I think it would be a good idea to add these extensions in if possible. They'll give us more linting coverage.

[ajkiessl]

A couple things. I have one comment below 👇 . Also, I think we need to add this:

AllCops:
    NewCops: enable

to the rubocop.yml. I think this should get around the error. It also might fix the issue below.

[ajkiessl]

I don't think you need to split these up. Just running rubocop should cover the others. It's been a while since I've set up rubocop, though, so i may be wrong. If they're not running together, then we should find a way to get them to run together.

[ddecollo]

It is running with Rubocop. This command would give the option to only run on Rubocop for Rspec.

[ajkiessl]

I mean that just running bundle exec rubocop should run all the cops (basic rubocop, rails, and rspec). We don't want to split it up into 3 different instances.

[ddecollo]

They run together. This is just an additional option to only run rubocop for rspec

[ajkiessl]

Ok, then we should remove the rubocop-rails and rubocop-rspec CI "run" instances and just do the regular rubocop one. When we meet again we should go over how CI works and how these configs work to run certain commands.