Initial commit: KeepItGoing task management server

Features:
- Django-based REST API with web interface
- Task management with tags, priorities, and due dates
- Time tracking with start/stop timers
- Subtasks support
- Task filtering (all, today, upcoming, overdue, completed)
- Tag-based organization with color coding
- Sorting by due date and priority
- Auto-assign tags when filtering
- Responsive 3-pane layout (sidebar, task list, detail panel)
- Task sharing between users
- Mobile-responsive design with dark mode support

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

users/models.py

@@ -0,0 +1,69 @@
+"""
+User models for KeepItGoing.
+"""
+
+import uuid
+from django.contrib.auth.models import AbstractUser
+from django.db import models
+
+
+class User(AbstractUser):
+    """
+    Custom user model for KeepItGoing.
+
+    Uses email as the primary identifier instead of username.
+    """
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    email = models.EmailField(unique=True)
+
+    # Profile fields
+    timezone = models.CharField(max_length=50, default='UTC')
+    avatar = models.ImageField(upload_to='avatars/', null=True, blank=True)
+
+    # Preferences
+    default_reminder_minutes = models.IntegerField(default=30)
+    email_notifications = models.BooleanField(default=True)
+    push_notifications = models.BooleanField(default=True)
+
+    # Timestamps
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    # Use email as the username field
+    USERNAME_FIELD = 'email'
+    REQUIRED_FIELDS = ['username']
+
+    class Meta:
+        db_table = 'users'
+        verbose_name = 'user'
+        verbose_name_plural = 'users'
+
+    def __str__(self):
+        return self.email
+
+
+class DeviceToken(models.Model):
+    """
+    Stores push notification tokens for user devices.
+    """
+    PLATFORM_CHOICES = [
+        ('android', 'Android'),
+        ('web', 'Web'),
+        ('desktop', 'Desktop'),
+    ]
+
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='device_tokens')
+    platform = models.CharField(max_length=20, choices=PLATFORM_CHOICES)
+    token = models.TextField()
+    device_name = models.CharField(max_length=255, blank=True)
+    is_active = models.BooleanField(default=True)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        db_table = 'device_tokens'
+        unique_together = ['user', 'token']
+
+    def __str__(self):
+        return f"{self.user.email} - {self.platform} - {self.device_name}"