add setup generator

lib/generators/enju_inventory/setup/USAGE

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

lib/generators/enju_inventory/setup/setup_generator.rb

@@ -0,0 +1,13 @@
+class EnjuInventory::SetupGenerator < Rails::Generators::Base
+  source_root File.expand_path('../templates', __FILE__)
+
+  def copy_setup_files
+    inject_into_file 'app/controllers/application_controller.rb',
+      "  include EnjuInventory::Controller\n", after: "EnjuLibrary::Controller\n"
+    append_to_file("app/models/user.rb") do
+      <<"EOS"
+Item.include(EnjuInventory::EnjuItem)
+EOS
+    end
+  end
+end