Added '/api' to readme.
Added '/api' to readme.

dgtester/cromwell,broadinstitute/cromwell,ohsu-comp-bio/cromwell,dgtester/cromwell,broadinstitute/cromwell,broadinstitute/cromwell,broadinstitute/cromwell,cowmoo/cromwell,cowmoo/cromwell,cowmoo/cromwell,ohsu-comp-bio/cromwell,ohsu-comp-bio/cromwell,dgtester/cromwell,broadinstitute/cromwell