add rspec, 12 factor to requirements
add Paper model
switching back from rspec
add citation model
add has_many :citations to paper
add has_many :through for citing, cited papers
add tests for citation text
citations should be unique for a->b
Merge pull request #1 from ploslabs/feature/papers_model

I'm going to merge this so that I can work. Just issue a new pull request when you are done.