Create a detailed set of instruction for deploying the bot in production.

[smover]

Produce a detailed instruction about the deployment that is accessible without reading the probot documentation. The link provided in the README is too generic and does not describe the real parameters of our app.

Sriram and myself should be able to read the documentation and deploy the github app.

Also, please add the documentation about testing the bot locally (i.e., when developing).

The documentation can be in the main README or in a separate markdown document.