Merge pull request #7 from alexcodreanu86/posts

can now create posts from form and view the newly created post on the sh...
Tests for sign up and sign in created, along with test to ensure the errors are displaying when the user makes a mistake.
fixed some conflicts in spec_helper.rb
Merge pull request #8 from alexcodreanu86/user

User
index view that displays all posts.
Posts now show up in descending order

Posts are shown in descending order by post.id. This should be effectively the same as
showing in reverse chronological order as post id is autogenerated upon creation.