Adding addons to ERPNext

Hello ERPNext community
I have an app which I would like to install it on frappe
I have ran the following:

bench get-app [app-name] [github-link]
bench --site [site-name] install-app [app-name]

I got this error:
could not find app [app-name]

any ideas? :smiling_face_with_three_hearts: ling

Note: app is already in the apps folder but not on the sites/apps.txt file.