Problem description
I'm trying to integrate Harbormaster with GoCD (gocd.io). The problem I'm facing is that GoCD expects to see some HTTP headers in HTTP requests to its API. For example, to trigger a pipeline (or build) the request should look like this:

$ curl 'http://ci.example.com/go/api/pipelines/pipeline1/schedule' \
       -u 'username:password' \
       -H 'Confirm: true' \
       -X POST

Without the header 'Confirm: true', GoCD responds with:

The url you are trying to reach appears to be incorrect.

Feature Request
Add "HTTP Headers" field to Harbormaster's "Make HTTP Request" build step. This will make possible to work with a broader range of HTTP APIs, not onlty with GoCD.