Merge #​2667 "Work around bug in migrations to non-null columns"

db/migrate/20170715131706_make_track_state_not_null_and_add_default_value.rb

@@ -6,6 +6,8 @@ class MakeTrackStateNotNullAndAddDefaultValue < ActiveRecord::Migration[4.2]
   end
 
   def change
+    TmpTrack.reset_column_information
+
     TmpTrack.where(state: nil).each do |track|
       track.state = 'confirmed'
       track.save!

db/migrate/20170720134353_make_track_cfp_active_not_null.rb

@@ -6,11 +6,13 @@ class MakeTrackCfpActiveNotNull < ActiveRecord::Migration[4.2]
   end
 
   def change
+    TmpTrack.reset_column_information
+
     TmpTrack.where(cfp_active: nil).each do |track|
       track.cfp_active = true
       track.save!
     end
 
-    change_column_null :tracks, :cfp_active, false
+    change_column :tracks, :cfp_active, :boolean, null: false, default: false
   end
 end