Remove move_diff_fields manual migration
Remove move_diff_fields manual migration

This manual migration was needed for folks who wanted to preserve data
after we moved some columns around. Enough time has passed where we
don't feel like it is generally useful anymore. If you still need to run
it, you can get the file back easily by executing:

  git show 5e89f43:app/services/manual_migrations.rb > app/services/manual_migrations.rb

Closes #65

Change-Id: I79cb5a5e189f9a9e7549def93430fd349f57b384

kalw/diffux,kalw/diffux,diffux/diffux,diffux/diffux,diffux/diffux,kalw/diffux