bug(docker): fix missing hostname when running flask in docker

docs/docs/11_deploy_to_render/03_docker_with_gunicorn/README.md

@@ -62,9 +62,9 @@ If you use this `Dockerfile`, it doesn't mean you can't run it locally using the
 To run the Docker container locally, you'll have to do this from now on:
 
 ```zsh
-docker run -dp 5000:5000 -w /app -v "$(pwd):/app" teclado-site-flask sh -c "flask run"
+docker run -dp 5000:5000 -w /app -v "$(pwd):/app" teclado-site-flask sh -c "flask run --host 0.0.0.0"
 ```
 
-This is similar to how we've ran the Docker container with our local code as a volume (that's what `-w /app -v "$(pwd):/app"` does), but at the end of the command we're telling the container to run `flask run` instead of the `CMD` line of the `Dockerfile`. That's what `sh -c "flask run"` does!
+This is similar to how we've ran the Docker container with our local code as a volume (that's what `-w /app -v "$(pwd):/app"` does), but at the end of the command we're telling the container to run `flask run --host 0.0.0.0` instead of the `CMD` line of the `Dockerfile`. That's what `sh -c "flask run --host 0.0.0.0"` does!
 
 Now you're ready to commit and push this to your repository and re-deploy to Render.com!