Add acts-as-votable; generate migration for a-a-v
add acts-as-votable to completions
add acts-as-voter to users
Add acts-as-voter to index.haml; fix migrations
add buttons for up/downvotes
change buttons to links; add class for styling
Merge branch 'master' into acts-as-votable
Merge branch 'master' into acts-as-votable
add associations for votes