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/serializers.py

@@ -0,0 +1,95 @@
+"""
+User serializers for KeepItGoing API.
+"""
+
+from django.contrib.auth import get_user_model
+from django.contrib.auth.password_validation import validate_password
+from rest_framework import serializers
+from .models import DeviceToken
+
+User = get_user_model()
+
+
+class UserSerializer(serializers.ModelSerializer):
+    """Serializer for user details."""
+
+    class Meta:
+        model = User
+        fields = [
+            'id', 'email', 'username', 'first_name', 'last_name',
+            'timezone', 'avatar', 'default_reminder_minutes',
+            'email_notifications', 'push_notifications',
+            'created_at', 'updated_at',
+        ]
+        read_only_fields = ['id', 'email', 'created_at', 'updated_at']
+
+
+class UserRegistrationSerializer(serializers.ModelSerializer):
+    """Serializer for user registration."""
+
+    password = serializers.CharField(
+        write_only=True,
+        required=True,
+        validators=[validate_password],
+        style={'input_type': 'password'}
+    )
+    password_confirm = serializers.CharField(
+        write_only=True,
+        required=True,
+        style={'input_type': 'password'}
+    )
+
+    class Meta:
+        model = User
+        fields = ['email', 'username', 'password', 'password_confirm', 'first_name', 'last_name']
+
+    def validate(self, attrs):
+        if attrs['password'] != attrs['password_confirm']:
+            raise serializers.ValidationError({
+                'password_confirm': "Passwords do not match."
+            })
+        return attrs
+
+    def create(self, validated_data):
+        validated_data.pop('password_confirm')
+        user = User.objects.create_user(**validated_data)
+        return user
+
+
+class ChangePasswordSerializer(serializers.Serializer):
+    """Serializer for password change."""
+
+    old_password = serializers.CharField(
+        required=True,
+        style={'input_type': 'password'}
+    )
+    new_password = serializers.CharField(
+        required=True,
+        validators=[validate_password],
+        style={'input_type': 'password'}
+    )
+
+    def validate_old_password(self, value):
+        user = self.context['request'].user
+        if not user.check_password(value):
+            raise serializers.ValidationError("Current password is incorrect.")
+        return value
+
+
+class DeviceTokenSerializer(serializers.ModelSerializer):
+    """Serializer for device tokens."""
+
+    class Meta:
+        model = DeviceToken
+        fields = ['id', 'platform', 'token', 'device_name', 'is_active', 'created_at']
+        read_only_fields = ['id', 'created_at']
+
+    def create(self, validated_data):
+        validated_data['user'] = self.context['request'].user
+        # Update if token already exists, otherwise create
+        device_token, created = DeviceToken.objects.update_or_create(
+            user=validated_data['user'],
+            token=validated_data['token'],
+            defaults=validated_data
+        )
+        return device_token