Create issue failed throws you to admin index and discards state

[sklirg]

If creating an issue fails for some reason, you get an error message that it failed and you get redirected to the admin index page. You lose all state of the issue and have to create it from scratch.

This happened when I had database level errors (e.g. missing a constraint or invalid values), so it might be possible to catch the exceptions and do some magic to stop this from happening, but I'm not fully sure.

This happened on #284.