specify rails version

lib/generators/geocoder/maxmind/geolite_city_generator.rb

 require 'rails/generators/migration'
+require 'generators/geocoder/migration_version'
 
 module Geocoder
   module Generators
     module Maxmind
       class GeoliteCityGenerator < Rails::Generators::Base
         include Rails::Generators::Migration
+        include Generators::MigrationVersion
 
         source_root File.expand_path('../templates', __FILE__)
 

lib/generators/geocoder/maxmind/geolite_country_generator.rb

 require 'rails/generators/migration'
+require 'generators/geocoder/migration_version'
 
 module Geocoder
   module Generators
     module Maxmind
       class GeoliteCountryGenerator < Rails::Generators::Base
         include Rails::Generators::Migration
+        include Generators::MigrationVersion
 
         source_root File.expand_path('../templates', __FILE__)
 

lib/generators/geocoder/maxmind/templates/migration/geolite_city.rb

-class GeocoderMaxmindGeoliteCity < ActiveRecord::Migration
+class GeocoderMaxmindGeoliteCity < ActiveRecord::Migration<%= migration_version %>
   def self.up
     create_table :maxmind_geolite_city_blocks, id: false do |t|
       t.column :start_ip_num, :bigint, null: false

lib/generators/geocoder/maxmind/templates/migration/geolite_country.rb

-class GeocoderMaxmindGeoliteCountry < ActiveRecord::Migration
+class GeocoderMaxmindGeoliteCountry < ActiveRecord::Migration<%= migration_version %>
   def self.up
     create_table :maxmind_geolite_country, id: false do |t|
       t.column :start_ip, :string

lib/generators/geocoder/migration_version.rb

+module Geocoder
+  module Generators
+    module MigrationVersion
+      def rails_5?
+        Rails::VERSION::MAJOR == 5
+      end
+
+      def migration_version
+        if rails_5?
+          "[#{Rails::VERSION::MAJOR}.#{Rails::VERSION::MINOR}]"
+        end
+      end
+    end
+  end
+end

test/db/migrate/001_create_test_schema.rb

 # CreateTestSchema creates the tables used in test_helper.rb
-class CreateTestSchema < ActiveRecord::Migration
+
+superclass = ActiveRecord::Migration
+# TODO: Inherit from the 5.0 Migration class directly when we drop support for Rails 4.
+superclass = ActiveRecord::Migration[5.0] if superclass.respond_to?(:[])
+
+class CreateTestSchema < superclass
   def self.up
     [
       :places,