Authorities have arrested a man who they say threatened the employee of a Portland restaurant with a knife and then barricaded himself inside an apartment.The Portland Police Department announced the arrest of Ryan Nutter following Thursday's incident.According to authorities, Nutter walked into the Front Room, a restaurant on Congress Street, and threatened an employee with a knife.Nutter then fled the area and went to his apartment on Sheridan Street, where he barricaded himself inside, officials said.The Portland Police Department added Nutter made threats to harm himself, as well as others.Nutter was taken into custody after surrendering to authorities. He was taken to Maine Medical Center and then to jail.He has been charged with criminal threatening with a dangerous weapon.