Do you plan to create a forum in the future, for example, with payment for constructive posts and add weekly contests? I think it would help attract more users.
If you meant having a signature campaign on the forum and not an actual community like bitcointalk, there is one, unfortunately, the signature campaign is on
hold. On the other hand, creating a forum community solely for JacksClub.io will not gain much traction in terms of advertising and it would cost them a lot of resources such in terms of paying annual domain name, cost for bandwidth and webspace etc.. It would do more harm than good. One thread and a few more contest held in bitcointalk itself is enough to get an attention.
As per the contests, JacksClub.io is currently running a few different wagering contest in their website. Check
that out.
There are a couple of live examples, but really, too much cost and time, and far from the fact that users will come. However, now online is too small, in the place of developers, I would do something similar.