Feature: Introduce Super Admins (#705)

* Feature: Introduce Super Admins

- added new devise model for super user
- added administrate gem
- sample dashboards for users and accounts

Co-authored-by: Pranav Raj Sreepuram <pranavrajs@gmail.com>

app/controllers/super_admin/accounts_controller.rb

@@ -0,0 +1,44 @@
+class SuperAdmin::AccountsController < SuperAdmin::ApplicationController
+  # Overwrite any of the RESTful controller actions to implement custom behavior
+  # For example, you may want to send an email after a foo is updated.
+  #
+  # def update
+  #   super
+  #   send_foo_updated_email(requested_resource)
+  # end
+
+  # Override this method to specify custom lookup behavior.
+  # This will be used to set the resource for the `show`, `edit`, and `update`
+  # actions.
+  #
+  # def find_resource(param)
+  #   Foo.find_by!(slug: param)
+  # end
+
+  # The result of this lookup will be available as `requested_resource`
+
+  # Override this if you have certain roles that require a subset
+  # this will be used to set the records shown on the `index` action.
+  #
+  # def scoped_resource
+  #   if current_user.super_admin?
+  #     resource_class
+  #   else
+  #     resource_class.with_less_stuff
+  #   end
+  # end
+
+  # Override `resource_params` if you want to transform the submitted
+  # data before it's persisted. For example, the following would turn all
+  # empty values into nil values. It uses other APIs such as `resource_class`
+  # and `dashboard`:
+  #
+  # def resource_params
+  #   params.require(resource_class.model_name.param_key).
+  #     permit(dashboard.permitted_attributes).
+  #     transform_values { |value| value == "" ? nil : value }
+  # end
+
+  # See https://administrate-prototype.herokuapp.com/customizing_controller_actions
+  # for more information
+end