refactor(backend): 更新数据库配置并迁移至MySQL，优化文档和技术栈描述

backend/docker-compose.yml

@@ -0,0 +1,26 @@
+version: '3.8'
+
+services:
+  mysql:
+    image: mysql:8.0
+    container_name: jiebanke-mysql
+    environment:
+      MYSQL_ROOT_PASSWORD: rootpassword
+      MYSQL_DATABASE: jiebanke_dev
+      MYSQL_USER: jiebanke_user
+      MYSQL_PASSWORD: jiebanke_pass
+    ports:
+      - "3306:3306"
+    volumes:
+      - mysql_data:/var/lib/mysql
+      - ./scripts/init-database.sql:/docker-entrypoint-initdb.d/init.sql
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost", "-u", "root", "-p$$MYSQL_ROOT_PASSWORD"]
+      interval: 10s
+      timeout: 5s
+      retries: 3
+
+volumes:
+  mysql_data:
+    driver: local