Add tests for Deploy#commits and Deploy#since_commit_id
Add tests for Deploy#commits and Deploy#since_commit_id

ershad/shipit-engine,perobertson/shipit-engine,Shopify/shipit-engine,Shopify/shipit-engine,perobertson/shipit-engine,ershad/shipit-engine,perobertson/shipit-engine,ershad/shipit-engine,perobertson/shipit-engine,Shopify/shipit-engine,perobertson/shipit-engine,Shopify/shipit-engine,ershad/shipit-engine,ershad/shipit-engine,Shopify/shipit-engine