A new optional argument "-b/--authenticationDatabase" has been added to specify that database. If not provided and authentication is required, mongotail will use the database specified in the db address.
Sorry, I saw this issue today, maybe Github never notify me, or maybe I didn't see the notification in my inbox. I will check the new feature and the code in the pull request in the incoming days.
This commit attempts to resolve issue #3.
A new optional argument "-b/--authenticationDatabase" has been added to specify that database. If not provided and authentication is required, mongotail will use the database specified in the db address.