Tox not passing environment variables

[4word]

Tests are failing in Travis because somehow, in the "passenv" section of the tox config, a leading dash is in front of the section name. Not sure how it snuck in, but it shouldn't be there and I believe its causing the tests to not test postgres or mysql specific code, since the default is sqlite if the environment variables are not found. It currently reads:

[testenv]
-passenv=
  DATABASE_URL
  SHARD_001_DATABASE_URL
  SHARD_002_DATABASE_URL
  REPLICA_001_DATABASE_URL
  REPLICA_002_DATABASE_URL
  TRAVIS

It should read

[testenv]
passenv=
  DATABASE_URL
  SHARD_001_DATABASE_URL
  SHARD_002_DATABASE_URL
  REPLICA_001_DATABASE_URL
  REPLICA_002_DATABASE_URL
  TRAVIS

[JBKahn]

ahhh I'll try to fix this tonight.

[4word]

I think this can be closed now, PR #29