Rename command to remove a name conflict.

accountant/run.py

@@ -18,12 +18,12 @@ app = create_app(config_path)  # pylint: disable=invalid-name
 
 # Define commands to handle users.
 @app.cli.group()
-def user():
+def users():
     """ User management. """
     pass
 
 
-@user.command()
+@users.command()
 def add(email, password):
     """ Add a new user. """
     user = User()