Added Authentication Model
fixed user_id references
Fixed erroneous double vote counting behavior

Added ordering by score to story model and list method in story controller
Changed show view to a partial
Changed user_id in the story model to a string
Fixed story model so that it retrieves stories with no votes in the find_by_score method

Added seed data
Made downvoting configurable
Merge pull request #7 from active911/create_authentication_model

Create authentication model and switch to upvote only default