San Francisco-based Forerunner Ventures is best known for its long string of bets on successful and fast-growing consumer companies. Now, its newest partner, Brian O’Malley, who has a knack for finding startups that straddle both the consumer and enterprise worlds, has written his first check on behalf of the firm, and it’s largely in that same vein. The company: Homeroom, a two-year-old, 12-person, San Francisco-based marketplace business focused around after-school enrichment programs.