self.up works in rails2 and rails3, but up only works in rails3+
also tag the switchman migrations as RAILS3 only, now that they actually
run in rails2
Change-Id: I768c8e657e86de6504a40444d127e2d875ce6934
Reviewed-on: https://gerrit.instructure.com/35390
Tested-by: Brian Palmer <brianp@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: Brian Palmer <brianp@instructure.com>
QA-Review: Brian Palmer <brianp@instructure.com>