conference date format
add missing timestamps
put `null: false` back by explicit declaration
ensure there won't be NULLs in the comments timestamps
Merge pull request #39 from rails-girls-summer-of-code/db_consistency

minor database updates
adding irc handle to team overview, should be half of #36
adding Team location to the model
add team location to overview
cleaning up merge leftovers
fix tests and fix feed item source url for atom feeds with local links
Merge pull request #41 from pxlpnk/add_irc_handle_and_location_to_team_overview

Add irc handle and location to team overview
fix merge conflicts
location might be blank
only use students location