It looks like you are missing the JBDC driver. Did you deploy the module:
and the actual JAR file (of the JDBC driver) ?
mvn dependency:copy -Dartifact=mysql:mysql-connector-java:5.1.18 -DoutputDirectory=/Path/to/JBossAS/modules/com/mysql/jdbc/main/
(Oh, just in case.... for WildFly the script is _slightly_ different - not yet there)
In any case, for simple starters, I'd highly recommend using the H2 database. Simply copy the DS-XML file into $JBOSS (or $WILDFLY) /standalone/deployments
(yes - that works w/ WildFly as well - as is, no modification needed)
Greetings,
Matthias