refresh readme

README.md

@@ -1,9 +1,25 @@
 # mysqldump
 
+## Description
+
+This Docker image provides the `mysqldump` command. Generally, this command is bundled with MySQL Server, and you might not always want to install MySQL on the server that needs to do the backups. So this is a nifty way to run `mysqldump` without installing anything. Furthermore, it avoids warnings in output!
+
 ## Usage
 
-Use docker env to configure the ``~/.my.cnf`` file used by mysqldump.
+Environment values required:
+
+* `MYSQL_USER`
+* `MYSQL_PASSWORD`
+* `MYSQL_HOST`
+* `MYSQL_PORT` (optional if default)
+* `your-database-name`
+
+Example:
 
 ~~~bash
-docker run --rm -e MYSQL_USER=your-mysql-user -e MYSQL_PASSWORD=your-passowrd -e MYSQL_HOST=your-mysql.example.com -e MYSQL_PORT=3306 -v $(pwd):/out ghcr.io/deltablot/mysqldump -r /out/dump.sql your-database-name
+docker run --rm -e MYSQL_USER=your-mysql-user \
+  -e MYSQL_PASSWORD=your-passowrd \
+  -e MYSQL_HOST=your-mysql.example.com \
+  -e MYSQL_PORT=3306 \
+  -v $(pwd):/out ghcr.io/deltablot/mysqldump -r /out/dump.sql your-database-name
 ~~~