Hygiene: Add tmp dir to gitignore
Hygiene: Add tmp dir to gitignore

This way I can put some temporary output files that still show up
in IntelliJ, so I can diff between them, but don't get added to Git.

Change-Id: I88e62598bfb93f38dd07a564521ca7896f02a03d

wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps