include explicit post request through handle_setopt

[lehighKent]

I've found myself seeking out this SO question repeatedly for making very explicit post requests.

[jeroen]

Setting customrequest here is redundant; the POST method is implicit when setting postfields.

In fact, setting the method manually with curl is almost always unnecessary and discouraged: https://daniel.haxx.se/blog/2015/09/11/unnecessary-use-of-curl-x/