add baselayer column to gtt_tile_sources table

Author: mbasa

db/migrate/20210812013250_add_default_to_tile_sources3.rb

@@ -0,0 +1,5 @@
+class AddDefaultToTileSources < ActiveRecord::Migration[5.2]
+  def change
+    add_column :baselayer, :default, :boolean, default: true
+  end
+end