I didn't mean to change all occurrences of `credentialsId` to `credentials_id`. I believe this should be 
```ruby
"credentialsId" => params[:credentials_id]
```
or else jenkins wouldn't be able to recognize it. What I meant is that Jenkins uses the Java notation for attribute names and we wanted to keep it in Ruby style and then passing it correctly when passing it to Jenkins remote API. Is that clear?

Also if you could test it once, I would really appreciate it.