Update 68.5.2. Execute Liquibase database migrations on startup.md

IX. ‘How-to’ guides/68.5.2. Execute Liquibase database migrations on startup.md

@@ -0,0 +1,7 @@
+### 68.5.2. 启动时执行Liquibase数据库迁移
+
+想要在启动时自动运行Liquibase数据库迁移，你需要将`org.liquibase:liquibase-core`添加到classpath下。
+
+主改变日志（master change log）默认从`db/changelog/db.changelog-master.yaml`读取，但你可以使用`liquibase.change-log`进行设置。详情查看[LiquibaseProperties](http://github.com/spring-projects/spring-boot/tree/master/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/liquibase/LiquibaseProperties.java)以获取可用设置，比如上下文，默认的schema等。
+
+这里有个[Liquibase示例](http://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples/spring-boot-sample-liquibase)可作为参考。