readme: add mariadb alongside mysql

README.md

@@ -23,6 +23,7 @@ proper schema versioning and migration rollback support.
 It supports any of the [databases Gorm supports](https://gorm.io/docs/connecting_to_the_database.html):
 
 - MySQL
+- MariaDB
 - PostgreSQL
 - SQLite
 - Microsoft SQL Server
@@ -212,6 +213,9 @@ Then:
 # run test for MySQL
 task test:mysql
 
+# run test for MariaDB
+task test:mariadb
+
 # run test for PostgreSQL
 task test:postgres