Our unicorn config requires dotenv

* In each project we have a unicorn config
that does a Dotenv.load to reload any .env file
changes. If the project using that config does not have the
dotenv gem the unicorn:reexec command will not reload
the .env
* setting to an older version 0.9 instead of 0.10 because
our projects are using snapshot which only is compatible
with dotenv (0.9.0)