PR geerlingguy#240: Add documentation on deleting databases.

Author: geerlingguy

README.md

@@ -58,6 +58,8 @@ A list of files that should override the default global my.cnf. Each item in the
 
 The MySQL databases to create. A database has the values `name`, `encoding` (defaults to `utf8`), `collation` (defaults to `utf8_general_ci`) and `replicate` (defaults to `1`, only used if replication is configured). The formats of these are the same as in the `mysql_db` module.
 
+You can also delete a database (or ensure it's not on the server) by setting `state` to `absent` (defaults to `present`).
+
     mysql_users: []
 
 The MySQL users and their privileges. A user has the values: