adding to the Score module to calculate expected values of beers based on user
1) unrated_beers method returns an array of unrated beers of current user compared to another user
2) expected_value_of_unrated_beers method returns a hash of the expected values of unrated beers of current user compared to another user
3) all_expected_values_of_unrated_beers method returns a hash of all expected values of unrated beers by all other users
beer_sim_sum method returns the similarity scores between a user and those who have reviewed a particular beer
added total_by_sim_sum method which returns the total expected value divided by similarities for a beer to adjust for weighting
troubleshooting sim sums
adjusted navbar so that a first time user doesn't see top ten option until dictionary has been repopulated with that new user's reviews
added pagination
removed current user from top 10 similar users list
updated beer show view for images from RateBeer
Merge pull request #26 from vikram7/vr-beer-recs

adding to the Score module to calculate expected values of beers