Add Devise to Gemfile
Configure Devise

* All necessary configuration files for Devise have been generated.
* Devise's secret key has been moved to an environment variable as a
  security measure.
Change Devise's Mailer Sender Address

* Devise's mailer sender address has been changed to an environment
  variable.

NOTE: Please be sure to set the following enviornment variables so that
      there will be a valid mailer sender email address for each
      environment:

      * DEVELOPMENT_DEVISE_MAILER_SENDER
      * STAGING_DEVISE_MAILER_SENDER
      * PRODUCTION_DEVISE_MAILER_SENDER
      * TEST_DEVISE_MAILER_SENDER
Change Default Hosts to Environment Variables

* Changed the default hosts for all environments to environment
  variables for easier management.

NOTE: Be sure to set the following environment variables so that any
      emails come from the correct URL:

      * DEVELOPMENT_DEFAULT_URL
      * STAGING_DEFAULT_URL
      * PRODUCTION_DEFAULT_URL
      * TEST_DEFAULT_URL
Add Devise User

* The Devise user has been initialized.

NOTE: There is no migration for this.  This is due to the fact that
somehow it was already done during Suspenders configuration.
Add Sign In / Sign Out Links
Generate Devise Views
Fix Page Title Rendering

* Page titles were not displaying correctly, so I fixed them.  Hopefully
  they'll work the same way when this goes to production.
Convert Devise Pages to Haml

All Devise pages have been converted to Haml, with internationalization
already built in.
Turn Devise Shared Links into Buttons
Add Mailtrap Settings

* All Mailtrap settings are controlled by environment variables.
Add Devise Confirmable Module

* Users can now be confirmed with a quick email.
Add Devise Lockable Module
Add Edit Account Button to Right Navigation Panel
Add Environment Variables to README

Finally added information on what environment variables need to exist
for the app to work properly in all environments.