anchor.diff:  This assumes you have PostgreSQL already running on your computer and configured as a "module"
   in the WildFly server.
   
  -Since JPA uses PreparedStatements, and since the point of this app is to demonstrate
  -an XA commit, you have to tell PostgreSQL to allow prepared transactions. Try setting
  +Since the point of this app is to demonstrate an XA commit, you have to tell PostgreSQL to allow 
  +"prepared transactions". Try setting
   
   max_prepared_transactions = 20
   
  -in _postgres.conf_ (whereever that is on your system; to give you a couple of data points,
  +in _postgres.conf_ (wherever that is on your system; to give you a couple of data points,
   on OS X it is /Users/postgres/data/postgresql.conf and on OpenBSD it is 
   /var/postgresql/data/postgresql.conf ).
   
  
positive.code: You want to verify outside of the app:
  
  ----
  psql -d xademo_customers
  select * from customer;
  # You should see one customer with non-zero orders:
  
  xademo_customers=# select * from customer;
   id | name  | numberoforders | version 
  ----+-------+----------------+---------
    1 | Alpha |              2 |       2
  (1 row)
  
  \c xademo_orders
  select * from orders;
  # You should see order(s) with quantity 42, none with quantity 86:
  
  xademo_orders=# select * from orders;
   id |    date    | quantity | version 
  ----+------------+----------+---------
   -1 |            |        0 |     100
    2 | 2015-06-24 |       42 |       0
    3 | 2015-06-24 |       42 |       0
  (3 rows)
  
  ----
  
  The order with id of -1 is a placeholder put there during app startup, and can be ignored
  
negative.code: . psql -c 'drop database xademo_orders'
  . Remove the two datasource definitions from Wildfly standalone.xml
  . Restart Wildfly
  
  Hope you enjoyed this project!
  