Run also migrations in subdirectories.

With this commit, ActiveRecord will also look for migrations
in db/migrate subdirectories.

activerecord/lib/active_record/migration.rb

@@ -610,10 +610,11 @@ module ActiveRecord
         migrations_paths.first
       end
 
-      def migrations(paths)
+      def migrations(paths, subdirectories = true)
         paths = Array.wrap(paths)
 
-        files = Dir[*paths.map { |p| "#{p}/[0-9]*_*.rb" }]
+        glob = subdirectories ? "**/" : ""
+        files = Dir[*paths.map { |p| "#{p}/#{glob}[0-9]*_*.rb" }]
 
         seen = Hash.new false
 

activerecord/test/cases/migration_test.rb

@@ -1346,6 +1346,15 @@ if ActiveRecord::Base.connection.supports_migrations?
       end
     end
 
+    def test_finds_migrations_in_subdirectories
+      migrations = ActiveRecord::Migrator.new(:up, MIGRATIONS_ROOT + "/valid_with_subdirectories").migrations
+
+      [[1, 'ValidPeopleHaveLastNames'], [2, 'WeNeedReminders'], [3, 'InnocentJointable']].each_with_index do |pair, i|
+        assert_equal migrations[i].version, pair.first
+        assert_equal migrations[i].name, pair.last
+      end
+    end
+
     def test_finds_migrations_from_two_directories
       directories = [MIGRATIONS_ROOT + '/valid_with_timestamps', MIGRATIONS_ROOT + '/to_copy_with_timestamps']
       migrations = ActiveRecord::Migrator.new(:up, directories).migrations

activerecord/test/migrations/valid_with_subdirectories/1_valid_people_have_last_names.rb

@@ -0,0 +1,9 @@
+class ValidPeopleHaveLastNames < ActiveRecord::Migration
+  def self.up
+    add_column "people", "last_name", :string
+  end
+
+  def self.down
+    remove_column "people", "last_name"
+  end
+end

activerecord/test/migrations/valid_with_subdirectories/sub/2_we_need_reminders.rb

@@ -0,0 +1,12 @@
+class WeNeedReminders < ActiveRecord::Migration
+  def self.up
+    create_table("reminders") do |t|
+      t.column :content, :text
+      t.column :remind_at, :datetime
+    end
+  end
+
+  def self.down
+    drop_table "reminders"
+  end
+end

activerecord/test/migrations/valid_with_subdirectories/sub1/3_innocent_jointable.rb

@@ -0,0 +1,12 @@
+class InnocentJointable < ActiveRecord::Migration
+  def self.up
+    create_table("people_reminders", :id => false) do |t|
+      t.column :reminder_id, :integer
+      t.column :person_id, :integer
+    end
+  end
+
+  def self.down
+    drop_table "people_reminders"
+  end
+end