Q2A has been distributed under GNU GPL V2 (or later) license. If my understanding is correct, you can fork proudly. Gid (Q2A founder) also recommends it. However, you must apply GPL license to your production according to copyleft rule. Reference:
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.