Bug 1312839 - Properly document pulse data ingestion config
Bug 1312839 - Properly document pulse data ingestion config

The previous docs incorrectly said to use a settings_local.py file.
The correct way to define the Pulse URL is via an environment
variable.

tojonmz/treeherder,kapy2010/treeherder,KWierso/treeherder,tojonmz/treeherder,edmorley/treeherder,tojon/treeherder,tojon/treeherder,tojonmz/treeherder,edmorley/treeherder,edmorley/treeherder,kapy2010/treeherder,KWierso/treeherder,edmorley/treeherder,kapy2010/treeherder,tojonmz/treeherder,KWierso/treeherder,tojonmz/treeherder,tojon/treeherder,KWierso/treeherder,kapy2010/treeherder,tojonmz/treeherder,tojon/treeherder,kapy2010/treeherder