Well, no, that is not precisely what you are doing. You are asking for pen-testing. Zajd is saying you need to 1) let the community audit your source code, and/or 2) rewrite the website using modern development practices. An example already mentioned here is that passwords aren't handle with current best practices.

Appears that zajd's original comment has been down-voted a lot, but I'm not sure people know that Project Euler has been struggling with hacking for over a year. Maybe time for more than patches.

Maybe I'm a bit confused, but it doesn't seem by your announcement that you are opening up the source, just inviting people to try and hack. Having the source open would make it much easier to spot security problems.