Add a config file for mariaDB (#605)

mariadb/Dockerfile

@@ -2,6 +2,8 @@ FROM mariadb:latest
 
 MAINTAINER Mahmoud Zalt <mahmoud@zalt.me>
 
+ADD my.cnf /etc/mysql/conf.d/my.cnf
+
 CMD ["mysqld"]
 
 EXPOSE 3306

mariadb/my.cnf

@@ -0,0 +1,7 @@
+# MariaDB database server configuration file.
+#
+# You can use this file to overwrite the default configuration
+#
+# For explanations see
+# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
+