Add install generator for migration and default model

lib/generators/the_moderator/install/USAGE

@@ -0,0 +1,8 @@
+Description:
+    Explain the generator
+
+Example:
+    rails generate install Thing
+
+    This will create:
+        what/will/it/create

lib/generators/the_moderator/install/install_generator.rb

@@ -0,0 +1,18 @@
+class TheModerator::InstallGenerator < Rails::Generators::Base
+  include Rails::Generators::Migration
+
+  source_root File.expand_path('../templates', __FILE__)
+
+  def copy_model
+    template 'moderation.rb', File.join('app', 'models', 'moderation.rb')
+  end
+
+  def create_migration
+    migration_template 'migration.rb', 'db/migrate/create_moderations.rb'
+  end
+
+  def self.next_migration_number(dirname)
+    ActiveRecord::Migration.next_migration_number(
+      current_migration_number(dirname) + 1)
+  end
+end

lib/generators/the_moderator/install/templates/migration.rb

@@ -0,0 +1,14 @@
+class CreateModerations < ActiveRecord::Migration
+  def self.up
+    create_table "moderations" do |t|
+      t.references :moderatable, polymorphic: true
+      t.text :data, :null => false
+
+      t.timestamps
+    end
+  end
+
+  def self.down
+    drop_table :moderations
+  end
+end

lib/generators/the_moderator/install/templates/moderation.rb

@@ -0,0 +1,3 @@
+class Moderation < ActiveRecord::Base
+  include TheModerator::ModerationModel
+end