Improve styling a little
Add support for multiple local repositories

Pollamatia can now follow different repositories. You still need to have
each one checked out, up to date and tracking the branch you want to
watch for commits on - that's a "limitation" of Git.

I'm storing the repository in the URL, since it's nice to have multiple
tabs open, each with a different repository.

Everything should auto-migrate but you will need to create a repo
manually in the db (using irb):

require './models/boot.rb'

r=Repo.new
r.github_commit_url = 'http://www.github.com/proj-name/repo-name/commit'
r.local_path = '/home/username/dev/git/proj-path'
r.name = 'Awesome'

Commit.update(repo_id: Repo.first.id)

r=Repo.new
r.github_commit_url = '...' # another repo commit path
r.local_path = '...' # another local git repo path
r.name = 'Amazing'

You then have to select the repo by putting /?repo=Amazing or
/?repo=Awesome in the URL. Don't worry, I'll improve this when I start
adding Javascript!