Use rails engine for migrations

README.md

@@ -12,29 +12,18 @@ Add *HasFriendship* to your Gemfile:
 gem 'has_friendship'
 ```
 
-After you install *HasFriendship*, you need to run the generator:
-
-    $ rails generate has_friendship
-
-The generator will copy a migration that creates `friendships` table. Run the migration to finish the setup.
+After you bundle *HasFriendship*, you need to copy migrations and migrate:
 
+    $ rails has_friendship:install:migrations
     $ rake db:migrate
 
-### Upgrading to 0.1.0
-
-`0.1.0` adds a blocking feature for friendables. This requires an additional
-column in the `friendships` table, and a migration should be run. You will need
-to run the generator and run the new migration.
+## Gem upgrades
 
-### Upgrading to 1.x.x
+After gem updates, it may be necessary to run subsequent migrations.
 
-If upgrading from <= 0.1.3 to 1.x.x, please run the following generator:
+    $ rails has_friendship:install:migrations
 
-    $ rails generate has_friendship_update
-
-Then, run the migration:
-
-    $ rake db:migrate
+Will install _new_ migrations if they're necessary.
 
 ## Usage
 

lib/generators/has_friendship/templates/create_friendships.rb → db/migrate/1_create_friendships.rb

@@ -1,4 +1,10 @@
-class CreateFriendships < ActiveRecord::Migration[4.2]
+if ActiveRecord.gem_version >= Gem::Version.new('5.0')
+  class CreateFriendships < ActiveRecord::Migration[4.2]; end
+else
+  class CreateFriendships < ActiveRecord::Migration; end
+end
+
+CreateFriendships.class_eval do
   def self.up
     create_table :friendships do |t|
       t.references :friendable, polymorphic: true

db/migrate/2_add_blocker_id_to_friendships.rb

@@ -0,0 +1,15 @@
+if ActiveRecord.gem_version >= Gem::Version.new('5.0')
+  class AddBlockerIdToFriendships < ActiveRecord::Migration[4.2]; end
+else
+  class AddBlockerIdToFriendships < ActiveRecord::Migration; end
+end
+
+AddBlockerIdToFriendships.class_eval do
+  def self.up
+    add_column :friendships, :blocker_id, :integer, default: nil
+  end
+
+  def self.down
+    remove_column :friendships, :blocker_id
+  end
+end

lib/generators/has_friendship_update/templates/update_friendships.rb → db/migrate/3_update_friendships.rb

@@ -1,4 +1,10 @@
-class UpdateFriendships < ActiveRecord::Migration[4.2]
+if ActiveRecord.gem_version >= Gem::Version.new('5.0')
+  class UpdateFriendships < ActiveRecord::Migration[4.2]; end
+else
+  class UpdateFriendships < ActiveRecord::Migration; end
+end
+
+UpdateFriendships.class_eval do
   def self.up
     add_column :friendships, :status_temp, :integer, index: true
     HasFriendship::Friendship.where(status: 'pending').update_all(status_temp: 0)

lib/has_friendship.rb

@@ -2,6 +2,8 @@
 
 require 'active_support'
 require 'active_record'
+require 'rails/engine'
+require 'has_friendship/engine'
 
 module HasFriendship
   extend ActiveSupport::Autoload
@@ -13,4 +15,4 @@ module HasFriendship
 
 ActiveSupport.on_load(:active_record) do
   extend HasFriendship::Friendable
-end
+end

lib/has_friendship/engine.rb

@@ -0,0 +1,5 @@
+module HasFriendship
+  class Engine < ::Rails::Engine
+    # isolate_namespace HasFriendship
+  end
+end