Hi folks, we are a distributed team across multiple timezones with 24/7 on-call rotation, previsouly using PagerDuty but unfortunately they are too expensive for us (an infant startup). We are now trying to use Google Calendar so everybody can see/edit entries but it's very error prone and too static, with no integration with anything we use. We would love to stick with Google Calendar though, however organizing overrides, swaps and exceptions is basically a pain... any suggestions on something else that is simple enough but that does the job well?