Mark track state as not null and add default value

The regular tracks are marked as 'confirmed'

db/migrate/20170715131706_make_track_state_not_null_and_add_default_value.rb

@@ -0,0 +1,14 @@
+class MakeTrackStateNotNullAndAddDefaultValue < ActiveRecord::Migration
+  class TmpTrack < ActiveRecord::Base
+    self.table_name = 'tracks'
+  end
+
+  def change
+    TmpTrack.where(state: nil).each do |track|
+      track.state = 'confirmed'
+      track.save!
+    end
+
+    change_column :tracks, :state, :string, null: false, default: 'new'
+  end
+end