Adds Postmark gem and environment variables.
Also adds a simple Procfile, since we've got a .env now. Start your server with `foreman s` from now on.
Ignore the .env
Add foreman to the Gemfile, update README with info about Postmark and Foreman.
Send the submitter and the cfp admins an email when a Proposal is created or updated.
Merge pull request #34 from jnf/jnf/mail_all_the_peoples

Jnf/mail all the peoples