by default there are two files in jbos_home/standalone/configuration directory (for AS 7):
add new users into users file and assign them one or more of following roles: user, admin, manager in roles.properties file
What can I do to add users and groups in mysql Jbpm5 en Task in order for them to access their task.
if you have your users stored in data base you need to configure JAAS login mdule in JBoss that uses data base as repository. Make sure to add users that should have access to console to one of the following groups : user, admin, manager
for configuring JBoss login module please check JBoss AS documentation