They're very much playing the long game here but the thinking is that if they can get their fans to hook up with each other and have babies, within a few years they'll have a load of new supporters with which to fill their ground.
They could do with them too. The average attendance at Coliseum Alfonso Perez is around 8,000, the second lowest in La Liga.
Anyway, the app's called Getafinder. Here's a demonstration.
Sexy football.