After the walker fight at the school in Episode 1, you need talk to EVERYONE in the courtyard when it says "Help AJ make friends".
Here's a list of everyone who need to be interacted/talked to:
Violet & Tenn
Louis & Omar (Game shows it as Louis & friend)
Mitch & Willy
Ruby
Aasim
After talking to everyone it should unlock :)
(It doesn't matter what order you talk to them in, it just matters that you talk to them)