Added User sign up form -- see notes

still need to add password and password confirmation columns to the DB.
do migration
Adding User authentication

mostly User Model
updated folder structure for /shared folder
Sign up form validation

and some styling
Added flash
database file is different

not sure why this is being tracked...
Merge remote-tracking branch 'origin/AddNewUserForm' into Add-Authentication
fixed the url for including articleControls
Merge remote-tracking branch 'origin/Add-Authentication'