What do you think about me training my neighbors dog to shut up?
Is here a reason you trained them to do that?
He always bothered me with barking.
A neighbor's barking dog is a common nuisance that people experience, but the best way to handle this situation is to calmly and rationally discuss the issue with your neighbors and let them take care of the issue.
I'm gonna hurt that dog one day though.
I sincerely hope that you never harm the dog, barking or not. Not only is it illegal, but it's immoral. The dog isn't yours and you should stay away from it. Once you speak with your neighbors I'm sure they'll work on solutions to the problem.