The hook-up app Tinder has become big business. More than a million people now pay for the premium version of the app, according to its parent company Match Group. The premium app provides features such as unlimited right swipes and the ability to match with people in different cities. It costs $10 per month or $20 per month, depending on the user’s age. Thanks in part to Tinder, the Match Group, which also runs Match.com and OkCupid, pulled in $260 million in revenue from its dating business in the first quarter, the company said this week.