Environment Variables Recipe doesn't support Unicorn

[robvolk]

Even thought the documentation says it does, the env_vars recipe doesn't support Unicorn.

If you look at the recipe, it only supports Passenger. Please add support for Unicorn!

[radamanthus]

On the Passenger stack, an Nginx reload is needed to start a new process that loads the environment variables. On the Unicorn stack, a new Unicorn master needs to be started via monit restart unicorn_master_appname and an Nginx reload is not needed.