Add userTransaction in get_started_faster_with_forge.textile

Add userTransaction to begin and commit the transaction to avoid javax.persistence.TransactionRequiredException

Without injection of userTransaction to begin and commit, i got the error as follows:

```
Caused by: javax.persistence.TransactionRequiredException: JBAS011469: Transaction is required to perform this operation (either use a transaction or extended persistence context)
	at org.jboss.as.jpa.container.AbstractEntityManager.transactionIsRequired(AbstractEntityManager.java:692)
	at org.jboss.as.jpa.container.AbstractEntityManager.persist(AbstractEntityManager.java:562)
	at demo.LanguageDao.insertTestData(LanguageDao.java:42)
	... 98 more
```