I added the users BengaliHindu and Nedol to the Toolforge project by visiting https://wikitech.wikimedia.org/w/index.php?title=Special:NovaProject&action=addmember&projectname=tools&member=BengaliHindu and https://wikitech.wikimedia.org/w/index.php?title=Special:NovaProject&action=addmember&projectname=tools&member=Nedol and clicking "Submit".
After a while, the resulting page (https://wikitech.wikimedia.org/wiki/Special:NovaProject) was empty. I looked at "Manage Projects" (same URL, but not reload with POST parameters, but a new request) and verified that the two users were now members of the Toolforge project and marked the requests as done.
But subsequent inspection showed that they hadn't been given their shell access rights ("shell" at https://wikitech.wikimedia.org/wiki/Special:UserRights). I have fixed that for the two users in question since.