Add abstract base class for Device, ActionPushNative::Record

Folowing Active Storage and Action Text patterns, so that we can change
DB configuration on that class using the load hooks.

Author: rosa

app/models/action_push_native/device.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module ActionPushNative
-  class Device < ApplicationRecord
+  class Device < Record
     include ActiveSupport::Rescuable
 
     rescue_from(TokenError) { destroy! }

app/models/action_push_native/record.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module ActionPushNative
+  class Record < ActiveRecord::Base
+    self.abstract_class = true
+  end
+end
+
+ActiveSupport.run_load_hooks :action_push_native_record, ActionPushNative::Record