How do you integrate Automation with TestRail Test Runs

I am new to TestRail and I am looking how difficult it would be to integrate my automation to publish results to TestRail. One issue that I am facing is with ID"s for the TestRun. Each time I create new TestRun test id's change which means I would have to change id mapping in my automation as well. Am i missing something here or is there a different way of doing this. I would imagine TestID's would remain the same but TestRun ID would change or something like that. Any help would be appreciated.