Create partial for errors

A general error message will now display when a user does not enter information correctly
Add errors partial to users#new template
Update sign-in and sign-out

Sign-in and sign up are now only shown once. Once the user is redirected to the dashboard, They can see who they are signed in as and have the option to sign out.
Correct syntax and naming inconsistencies
Remove unused gems

Spring, turbolinks, paperclip, and friendly_id are removed along with the in-app dependencies
Refer to user by username instead of email
Add class method to text_subject model

Shouts will be converted to all uppercase
Change to_params method in user model

username.parameterize was causing the URLs to always show up lowercase, causing errors for searches dependent on exact syntax. .paramterize was removed and the problem was solved.