GIT change remote url

I'm new to git, but not definitely new. just it a long time ago I switched to subversion and now trying to re-learn about git.

Now, I'm learning rails too, using great resources by Michael Hartl.
I was remind a lot about git there. the problem is coming when deploying to heroku, the result not as it should. so I took an initiative my-self. I deleted heroku-app that just created, with a plan to re-push with other new hero-app.

but it turns out, it yielding a notification about:

So, the solution to this is changing remote url of git.
using: git remote set-url

to do that here is the full-command I did: