Removed spec/factories/votes.rb which was a duplicate of spec/factories.rb

Updated factory to create a vote for an answer or a question
spec/factories.rb

Updated user model to include a method to check if the user already voted on a votable
app/models/user.rb

Added a method to sum the vote for a question
app/models/question.rb

Added a conditoiin on display of vite buttons
app/views/questions/show.html.erb

Added some tests on up and down votes on question
spec/models/vote_spec.rb