Updates docs with installation instructions

[justinvasel]

# Install in a virtual environment
virtualenv production
source production/bin/activate
python -m pip install snews_pt

# Test the install
snews_pt set-name -n [detector]
snews_pt test-connection --no-firedrill

[habig]

take a look at #132

Open question on adding virtualenv wrappers to the git methods too.

[habig]

A reminder that we need to fix the TEST detector name usage too (then we can eliminate the detector naming step. #131

Once the dev server is up to speed with the connection test, we should eliminate the --no-firedrill option #127