Completes sendgrid integration
Adds start event mail notif
Merge branch 'master' of https://github.com/DiegoGarza/EventFeed into sendgrid

Conflicts:
	app/mailers/user_mailer.rb
Merge branch 'sendgrid' of https://github.com/DiegoGarza/EventFeed into sendgrid

Conflicts:
	app/controllers/posts_controller.rb
New config sendgrid
Finishes sendgrid