已经设置了mongodb，mongoose等，但是当我尝试向数据库添加内容时，实际上并没有添加它

I'm using localhost and have all the modules set up correctly and I've checked that the database exists. When I type in localhost:3000/pods/add?firstName='John' it's supposed to add it to the database, but for some reason it isn't working. I'm using localhost and have all the modules se