Add collect.mysql.user flag to docs (#530)
Add collect.mysql.user flag to docs (#530)

Signed-off-by: Piotr Ziółkowski <0d0191da8991df36db32dfb7b22b1df2aea6fd77@gmail.com>
prometheus/mysqld_exporter,roman-vynar/mysqld_exporter,prometheus/mysqld_exporter,roman-vynar/mysqld_exporter