Create project for specified user gitlab API

Hi,

I’m trying to create a git project on my gitlab server for a specific user via the API.

I run the following command:

curl --header “PRIVATE-TOKEN: privatetokenthingy” -X POST “127.0.0.1:8888/api/v4/projects?/user/user_id=51&name=testproject”

I get no error but the project is made for the user root instead of the user with the id 51
what am I doing wrong?

I followed this site GITLAB API