Register of runner fails if slash in the end

→ gitlab-ci-multi-runner register
Please enter the gitlab-ci coordinator URL (e.g. http://gitlab-ci.org:3000/):
http://localhost:3000/ci/
Please enter the gitlab-ci token for this runner:
44cbb9df96ac178abdb6
Please enter the gitlab-ci description for this runner:
[iMac-dzaporozhets.local]: 
ERRO[0009] 44cbb9df Registering runner... forbidden     
FATA[0009] Failed to register this runner. Perhaps you are having network problems 

But works if remove slash in the end => http://localhost:3000/ci

cc @ayufan