This commit fixes an issue where the `job_tasks` endpoint
scaled poorly as the number of job tasks increased.
Note: This is a revert of a revert, because I felt this needed
code review and didn't want it on master yet. Sorry.
AC-1341
This commit adds three files to .gitignore, to support local development
using Vagrant VMs.
Regarding `awx/main/fixtures`: This is to allow for a dev's primary user
to be in a fixture, so it's easily loaded.