DS-2422 Add example to Union docs
DS-2422 Add example to Union docs

Change-Id: I577f1879bf1bc0c8d0b6176c09bac1a5093d6341

deepsense-io/seahorse-workflow-executor,deepsense-io/seahorse-workflow-executor,deepsense-io/seahorse-workflow-executor,deepsense-io/seahorse-workflow-executor