I've been using this in production long enough without issue that it is time to declare 1.0

If this is needed, I'll gladly accept a Pull Request.

Add a migration guide from OmniAuth 0.3

Add undocumented configuration option

I had a hard time figuring out how to configure the correct endpoints. Maybe it helps someone.

disable_ssl_verification is currently undocumented.

https://github.com/jeromegn/DocumentUp/issues/23#issuecomment-4821497