Add Docker deployment configuration

- Add Dockerfile for production (multi-stage build)
- Add Dockerfile.dev for development with hot reload
- Add docker-compose.yml with 5 services (web, mariadb, redis, celery-worker, celery-beat)
- Add docker-compose.dev.yml for development overrides
- Add .dockerignore for optimized builds
- Add docker/entrypoint.sh startup script
- Add .env.docker.example template
- Add Makefile for common commands
- Add deploy.sh for one-command deployment
- Update config/settings/selfhosted.py to support MariaDB via DATABASE_URL
- Add mysqlclient to requirements.txt for MariaDB support
- Update .gitignore to exclude .env.docker

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

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

config/settings/selfhosted.py

@@ -6,6 +6,7 @@ Use this for users running their own instance.
 
 import os
 import sys
+import dj_database_url
 from .base import *
 
 # Security
@@ -28,17 +29,50 @@ if DEBUG:
 
 ALLOWED_HOSTS = os.environ.get('ALLOWED_HOSTS', 'localhost,127.0.0.1').split(',')
 
-# Database - PostgreSQL for self-hosted
-DATABASES = {
-    'default': {
-        'ENGINE': 'django.db.backends.postgresql',
-        'NAME': os.environ.get('POSTGRES_DB', 'keepitgoing'),
-        'USER': os.environ.get('POSTGRES_USER', 'keepitgoing'),
-        'PASSWORD': os.environ.get('POSTGRES_PASSWORD', 'keepitgoing'),
-        'HOST': os.environ.get('POSTGRES_HOST', 'db'),
-        'PORT': os.environ.get('POSTGRES_PORT', '5432'),
+# Database - Support both PostgreSQL and MariaDB/MySQL via DATABASE_URL
+# DATABASE_URL format examples:
+#   PostgreSQL: postgresql://user:password@host:5432/dbname
+#   MariaDB/MySQL: mysql://user:password@host:3306/dbname
+database_url = os.environ.get('DATABASE_URL')
+
+if database_url:
+    # Use DATABASE_URL for flexible database backend (PostgreSQL, MariaDB, MySQL, etc.)
+    DATABASES = {
+        'default': dj_database_url.config(
+            default=database_url,
+            conn_max_age=600,
+            conn_health_checks=True,
+        )
     }
-}
+
+    # Add MariaDB/MySQL specific options if using MySQL backend
+    if 'mysql' in database_url.lower():
+        DATABASES['default']['OPTIONS'] = {
+            'charset': 'utf8mb4',
+            'init_command': "SET sql_mode='STRICT_TRANS_TABLES'",
+        }
+else:
+    # Fallback to manual configuration (backwards compatibility)
+    # Supports both PostgreSQL and MariaDB/MySQL
+    db_engine = os.environ.get('DB_ENGINE', 'django.db.backends.postgresql')
+
+    DATABASES = {
+        'default': {
+            'ENGINE': db_engine,
+            'NAME': os.environ.get('DB_NAME', os.environ.get('POSTGRES_DB', 'keepitgoing')),
+            'USER': os.environ.get('DB_USER', os.environ.get('POSTGRES_USER', 'keepitgoing')),
+            'PASSWORD': os.environ.get('DB_PASSWORD', os.environ.get('POSTGRES_PASSWORD', 'keepitgoing')),
+            'HOST': os.environ.get('DB_HOST', os.environ.get('POSTGRES_HOST', 'db')),
+            'PORT': os.environ.get('DB_PORT', os.environ.get('POSTGRES_PORT', '5432')),
+        }
+    }
+
+    # Add MariaDB/MySQL specific options if using MySQL backend
+    if 'mysql' in db_engine:
+        DATABASES['default']['OPTIONS'] = {
+            'charset': 'utf8mb4',
+            'init_command': "SET sql_mode='STRICT_TRANS_TABLES'",
+        }
 
 # Redis/Celery
 REDIS_URL = os.environ.get('REDIS_URL', 'redis://redis:6379/0')