更新了settings.py的内容，在开发环境和生产环境统一

.env.example

@@ -0,0 +1,13 @@
+# Django settings
+SECRET_KEY=your-secret-key
+DEBUG=True
+ALLOWED_HOSTS=127.0.0.1,localhost
+
+# Database settings
+# DATABASE_URL=sqlite:///db.sqlite3
+# For PostgreSQL: DATABASE_URL=postgres://user:password@localhost:5432/dbname
+# For MySQL: DATABASE_URL=mysql://user:password@localhost:3306/dbname
+
+# Static and media files
+STATIC_ROOT=static
+MEDIA_ROOT=media