Issue #814: See what files rubocop is inspecting.

Author: geerlingguy

.travis.yml

@@ -61,6 +61,7 @@ script:
   - '[[ ! -z "${local_config}" ]] && sudo docker exec "$(cat ${container_id})" bash -c "cp ${DRUPALVM_DIR}/${local_config} ${config_dir:-$DRUPALVM_DIR}/local.config.yml" || true'
 
   # Vagrantfile syntax check
+  - 'rubocop --list-target-files'
   - 'rubocop --except LineLength,Eval,MutableConstant'
 
   # Ansible syntax check.