Fix incorrect column name.

lib/generators/geocoder/templates/migration/maxmind_geolite_city.rb

@@ -15,9 +15,9 @@ class GeocoderMaxmindGeoliteCity < ActiveRecord::Migration
       t.string :postalCode, null: false
       t.float :latitude
       t.float :longitude
-      t.integer :dmaCode
+      t.integer :metroCode
       t.integer :areaCode
     end
     add_index :maxmind_location, :locId, unique: true
   end
-end
+end
\ No newline at end of file