Iowa is 92% white. Despite this, the campaign clearly made efforts to put many minorities in the video. Each one of these points in the video represent either a group of minorities or an individual minority in close with Sanders.

18 seconds
21 seconds
31 seconds
32 seconds
33-36 seconds (many many many)
37-39 seconds (crowd shots showing lots of people, including minorities)
40 seconds
41 seconds
43 seconds
44 seconds
46 seconds
52 seconds (crowd shots showing lots of people, including minorities)
57 seconds (minorities on stage)