Because of the concept introduced in here,

Rails::Plugin is nothing more than a Rails::Engine, but since it's loaded too late in the boot process, it does not have the same configuration powers as a bare Rails::Engine.

Opposite to Rails::Railtie and Rails::Engine, you are not supposed to inherit from Rails::Plugin. Rails::Plugin is automatically configured to be an engine by simply placing inside vendor/plugins. Since this is done automatically, you actually cannot declare a Rails::Engine inside your Plugin, otherwise it would cause the same files to be loaded twice. This means that if you want to ship an Engine as gem it cannot be used as plugin and vice-versa.

Besides this conceptual difference, the only difference between Rails::Engine and Rails::Plugin is that plugins automatically load the file "init.rb" at the plugin root during the boot process.

rake tasks in the rails plugins are deprecated and it is advised to use lib/tasks instead. How to solve this? Can I just simply move the plugin's tasks to the lib/tasks?