Was Ibrahim the Founder of Islam?

S 22:78 And wage jihad for Allah with his due jihad. He has selected you and has not put upon you in the religion any difficulty. The cult of your father Ibrahim. He named you Muslims before and in this, that the messenger may be a witness over you and you may be witnesses over people. So establish salat and give zakat and hang on to Allah. He is your mawla. So excellent was the mawla and excellent the helper.

Ibrahim evidently named Muslims thus. But don't Muslims assert that Allah named the religion? But if Ibrahim is naming its adherents Muslims... Does "in this" refer to quran? Where does Ibrahim name them Muslims in quran? Did Ibrahim name them in order that the unnamed messenger might be a witness over them and that they might be witnesses over people?

Further reading:

Jihad

Muslims

Cult

Ibrahim's Cult