[docs update]数据库部分内容描述

Author: Snailclimb

README.md

@@ -207,6 +207,7 @@ JVM 这部分内容主要参考 [JVM 虚拟机规范-Java8 ](https://docs.oracle
 - [InnoDB 存储引擎对 MVCC 的实现](./docs/database/mysql/innodb-implementation-of-mvcc.md)
 - [SQL 语句在 MySQL 中的执行过程](./docs/database/mysql/how-sql-executed-in-mysql.md)
 - [MySQL执行计划分析](./docs/database/mysql/mysql-query-execution-plan.md)
+- [MySQL自增主键一定是连续的吗](./docs/database/mysql/mysql-auto-increment-primary-key-continuous.md)
 - [MySQL 时间类型数据存储建议](./docs/database/mysql/some-thoughts-on-database-storage-time.md)
 - [MySQL 隐式转换造成索引失效](./docs/database/mysql/index-invalidation-caused-by-implicit-conversion.md)
 

docs/.vuepress/sidebar.ts

@@ -253,6 +253,7 @@ export const sidebarConfig = sidebar({
                 "innodb-implementation-of-mvcc",
                 "how-sql-executed-in-mysql",
                 "mysql-query-execution-plan",
+                "mysql-auto-increment-primary-key-continuous",
                 "some-thoughts-on-database-storage-time",
                 "index-invalidation-caused-by-implicit-conversion",
               ],