Issue Summary

When requesting the /subscribers/unsubscribed endpoint with 'page=0', we get a 500 error, yet on other endpoints 'page=0' works. This public release seems to indicate that pagination starts at 1, yet the API docs show that the default is 'page=0'

From the public docs under 'query parameters' for 'page': 

"Default: 0 The page offset of subscribers. The first page is page 0, the second page 1, etc. This skips page"

This is reproducible on Data Center: yes

Steps to Reproduce

send request to https://api.statuspage.io/v1/pages/{page_id}/subscribers/unsubscribed?page=0
send request to https://api.statuspage.io/v1/pages/{page_id}/subscribers/unsubscribed?page=1
send request to https://api.statuspage.io/v1/pages/{page_id}/subscribers?page=0
send request to https://api.statuspage.io/v1/pages/{page_id}/subscribers?page=1

Expected Results

All endpoints should function the same, but they do not. They should start at either 1 or 0, but there is inconsistency.

Actual Results

/subscribers/unsubscribed?page=0 throws 500 error while /subscribers?page=0 returns valid results for page 1. 

Workaround

start at index 1 for '/subscribers/unsubscribed' and start at index 0 for '/subscribers'