adds Notification mailer #44
Adds basic welcome email #44

adds Figaro application.yml
adds mail config for development
adds form and route for inviting users #44
Adds invite action and method #44

Users#invite for user invites
Notification member_invite delivers email
custom ids on invite form to avoid clashes
Adds email for invited members/admins #44

Controller handles admins and members
Notification passes variables to template
template for email
Sends email to invited/added users #44

Sends email to invited or added admins or users
Specs for notifications