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)
Fixing dotenv dependency at v0.0.8

* Shell variable expansion was added to
dotenv in v0.9.0 which causes some of
our .env files to break
* Rather than fixing all our .env files
just changing this for now (cause hopefully
we drop this gem)
Merge pull request #12 from amaabca/require-dotenv

Our unicorn config requires dotenv