What does it mean when a singer says red 1 in a song Like at the beginning of 'Just Dance' by Lady Gaga it says 'a red one'?

red 1 is a producer from Morocco produced songs like:
Lady Gaga - "Just Dance" (featuring Colby O'Donis)
Jennifer Lopez - "On The Floor" (featuring Pitbull)
Alexandra Burke - "Start Without You"
and more.
They are properly giving him credit