Ruby on rails - Hartl教程 - Micropost总是被检测为空白但它们不是

I have realized Hartl's tutorial about ruby on rails. I've almost completed it. Everything was working and I start to change some stuff, and now I've an error that I can't understand, about a thing that was working before. I've probably change something inadvertently but can't find what!I have realized Hartl's tutorial about ruby on