feat: added achievements

services/backend/apps/user/signals.py

@@ -0,0 +1,14 @@
+from django.db.models.signals import post_save
+from django.dispatch import receiver
+
+from apps.achievement.models import Achievement, UserAchievement
+from apps.user.models import User
+
+
+@receiver(post_save, sender=User)
+def assign_welcome_achievement(sender, instance, created, **kwargs):
+    if created:
+        welcome_achievement = Achievement.objects.get(slug="welcome")
+        UserAchievement.objects.create(
+            user=instance, achievement=welcome_achievement
+        )