:memo: add postgresql dump/restore

documents/PostgreSQL.md

@@ -0,0 +1,20 @@
+# PostgreSQL 常用命令
+
+用户名：www
+密码：change-me
+主机: 127.0.0.1
+端口：5432
+数据库：demo
+
+- 导出数据库
+
+  ```bash
+  pg_dump -Z 9 -h 127.0.0.1 -p 5432 -U www demo > $HOME/tmp/demo-20221009.sql.gz
+  ```
+
+- 导入数据库
+
+  ```bash
+  gunzip demo-20221009.sql.gz
+  psql -h 127.0.0.1 -p 5432 -U www demo < demo-20221009.sql
+  ```