You can find some freelancers if you don't want to hire a big staff and dont have much space for it.
There are coworking spaces as well - where you work and get benefited without creating your new office.
It's a serious business and by just hiring freelancers, it's like a quick and finis task without having the connection from those developers. You may hire them again in the future if there's something wrong with their work mostly for the codes.
Better to hire organizations that would help you build out the entire business and can maintain it for the sake of your customers, that's what it should be because security and maintaining it on its form is a must.
Aaaand on top of that ... you need a great matketing strategy , otherwise any great great services or products will never get any user and gonna be an abandoned project , remember just remember ... the goal is to make money and without having those marketing strategy , your project / casino will become nothing.
Get your code up , build an extraordinary addicting game and do the continuous promotion , all of these must be done in perfect way, all of them.