relocate db file
let foreman and shotgun require nothing when run Gemfile
add length validation for subscription email
add a column to exception_categories: wont_fix, means no notification for this category forever, don't calc its resolved percent into stats, whatever it's resolved or not doesn't matter any more.

wont_fix is designed for some exceptions which are from 3-rd party
service, although it's also exceptions, but no one can resolve it. Just
accept it and know.

wont_fix exceptions can still be marked as important, which means some
3-rd party exceptions could be important that we shouldn't ignore it
Finish all migrations