853 tweaked migration to fix db:migrate

[orenyk]

Resolves #853 by removing problematic lines in the migration.

[orenyk]

This also results in a schema conflict (it removes null: false from all of the created_at and updated_at fields). I haven't committed it yet but we can deal with that when it gets pulled in. I think this is an acceptable solution to the problem; any deployed instance that needs to run the unchanged migration (e.g. v3.4) will not run the changed migration when upgraded to v4.0, and any instance starting at v4.0 doesn't need those lines in the migration since the relevant table is simply dropped by the end.

[squidgetx]

What happens if someone who is late to the party tries to upgrade from 3.3 to 3.4 with this edited migration? Will the migrations run (and of lesser importance but still a valid question: will AA comments still work?)

[orenyk]

That's the beauty of it; the migration was only edited in v4.0. Anyone who checks out v3.4 will have the original migration.

[squidgetx]

Ah, I get it now.

Merge away!