feat: Refactor rides app with unique constraints, mixins, and enhanced documentation

- Added migration to convert unique_together constraints to UniqueConstraint for RideModel.
- Introduced RideFormMixin for handling entity suggestions in ride forms.
- Created comprehensive code standards documentation outlining formatting, docstring requirements, complexity guidelines, and testing requirements.
- Established error handling guidelines with a structured exception hierarchy and best practices for API and view error handling.
- Documented view pattern guidelines, emphasizing the use of CBVs, FBVs, and ViewSets with examples.
- Implemented a benchmarking script for query performance analysis and optimization.
- Developed security documentation detailing measures, configurations, and a security checklist.
- Compiled a database optimization guide covering indexing strategies, query optimization patterns, and computed fields.

backend/apps/accounts/models.py

@@ -49,8 +49,9 @@ class User(AbstractUser):
         domain="accounts",
         max_length=10,
         default="USER",
+        db_index=True,
     )
-    is_banned = models.BooleanField(default=False)
+    is_banned = models.BooleanField(default=False, db_index=True)
     ban_reason = models.TextField(blank=True)
     ban_date = models.DateTimeField(null=True, blank=True)
     pending_email = models.EmailField(blank=True, null=True)
@@ -127,6 +128,18 @@ class User(AbstractUser):
             return profile.display_name
         return self.username
 
+    class Meta:
+        indexes = [
+            models.Index(fields=['is_banned', 'role'], name='accounts_user_banned_role_idx'),
+        ]
+        constraints = [
+            models.CheckConstraint(
+                name='user_ban_consistency',
+                check=models.Q(is_banned=False) | models.Q(ban_date__isnull=False),
+                violation_error_message='Banned users must have a ban_date set'
+            ),
+        ]
+
     def save(self, *args, **kwargs):
         if not self.user_id:
             self.user_id = generate_random_id(User, "user_id")