John Hauldren has been a Chicago Cubs fan all his life. During the team’s last homestand, he got a text message from a high school friend. It was the first text he had received from him. Cubs center fielder Pete Crow-Armstrong had just used “Front to Back” — a song from Hauldren’s electronic music group, Levity — as his walkup music in a game against the Los Angeles Dodgers. Hauldren, who is from the Chicago suburbs, was in disbelief until he confirmed the moment himself. Levity played Coachella this year, and it is on the bill for Lollapalooza this summer.