I'm tired of entering the name of my app each time I run a heroku command in the terminal:
heroku run rake db:migrate --app myapp
heroku run rake db:seed --app myapp
heroku run rake sth:else --app myapp
The --app is very redundant and annoying, I didn't figured out where were the option to configure it globally once for the project.
heroku doesn't require the --app argument when it knows which app it should talk to. This occurs when there is exactly one Git remote pointing to Heroku for a repository.
You don't appear to have any remotes pointing to Heroku. Run
heroku git:remote --app myapp
to add such a remote. Once that's done you should be able to omit the --app argument for heroku commands on that particular repository.
If you prefer to do this yourself you can run
git remote add heroku [email protected]:myapp.git
Note that it's possible to have multiple Heroku remotes, e.g. if you have a staging and a production app. In this case you will also have to provide the --app argument to specify which one should be used.