Also, isn't it too early to monetize? Don't you want to accrue users before introducing premium?
For a Show HN I would have expected the ability to create tasks out of the box.
Also, instead of discouraging users from sharing code, you should embrace it via curation -- let people see other's solutions after they've submitted a solution of sufficient grade, let people code review each other's solutions, lots of low hanging fruit there that could be as simple as some automation on top of a private Github organization.
Do these companies who "contribute" tasks get to see the source code for the submissions?
The website aims to provide a list of projects for people to learn these skills (like uploading a file to AWS).
