ok, it's come up at least four times now

db/migrate/20120701154453_create_invitations.rb

@@ -1,3 +1,9 @@
+# If you are reading this file because Rails complains that there isn't a
+# version on this migration, stop.
+#
+# Create your database with `rails db:schema:load`, not by running all these.
+# We have migrations to migrate live databases, not create them, and we do not
+# want a PR to 'fix' migrations.
 class CreateInvitations < ActiveRecord::Migration
   def change
     create_table :invitations do |t|