Better stressque messaging about injector & sampler processes.
Testing behavior of encountering existing job classes.
Added Harness#freeze_jobs

So we fail fast if something is going to change our expected
runtime behavior.
Added rails demo site to demonstrate use with a rails app.
Specify redis connection string
Setup resque-stress to run in rails_demo app.

- Add gem to Gemfile
- Define a DSL
- Eval the DSL in the app on initialization.
Adding pry development dependencies
Better readme docs