Fix compile error

Tested in [Samba](https://github.com/grottopress/samba):

```
Showing last frame. Use --error-trace for full trace.

There was a problem expanding macro 'included'

Code in macro 'included'

 20 | include Shield::NotifyOauthAccessTokenIfSet
      ^
Called macro defined in lib/shield/src/shield/operations/mixins/notify_oauth_access_token_if_set.cr:2:3

 2 | macro included

Which expanded to:

 > 5 |       bearer_login = BearerLoginQuery.preload_oauth_client(bearer_login)
 > 6 |
 > 7 |       return unless bearer_login.user.settings.oauth_access_token_notify?
                                                      ^-------------------------
Error: undefined method 'oauth_access_token_notify?' for UserSettings
```

src/shield/models/user_settings.cr

@@ -2,15 +2,15 @@ module Shield::UserSettings
   macro included
     include Lucille::JSON
 
-    {% if Lucille::JSON.includers.find(&.name.== :BearerLogin.id) %}
+    {% if Avram::Model.all_subclasses.find(&.name.== :BearerLogin.id) %}
       include Shield::BearerLoginUserSettings
     {% end %}
 
-    {% if Lucille::JSON.includers.find(&.name.== :Login.id) %}
+    {% if Avram::Model.all_subclasses.find(&.name.== :Login.id) %}
       include Shield::LoginUserSettings
     {% end %}
 
-    {% if Lucille::JSON.includers.find(&.name.== :OauthClient.id) %}
+    {% if Avram::Model.all_subclasses.find(&.name.== :OauthClient.id) %}
       include Shield::OauthClientUserSettings
     {% end %}