If you have adminer listed as one of the installed_extras inside config.yml, you can use Adminer's web-based interface to interact with databases. With Drupal VM running, visit http://adminer.drupalvm.dev/, and log in with drupal as the username and the password you set in config.yml (drupal_db_password). Leave the "Server" field blank. The "Database" field is optional.

For a list of available role variables, see the geerlingguy.adminer Ansible role's README.