fix some build issues with votes
declare pg host to avoid occasional error

http://stackoverflow.com/questions/10791904/postgres-permission-denied-on-mac-os-x/10793186#10793186
Merge branch 'master' into votes
Add Voteable#has_vote_by_user

This will easily allow us to check if a user has alredy voted on an item with
a given vote_type
Add votes_by_user
Add Question#votes_on_self_and_answers_by_user(user)

This will be used to look up for whether votes are active with less DB queries