How to alter byCategory projection via API?

I want to set my “byCategory” system projection to last. Is there any way to do this automatically? Either via a startup configuration or an API call?

Appreciate any help.

Screen Shot 2018-04-04 at 2.26.30 PM.png

I tried (by inspecting the chrome browser request):

curl -H ‘Content-Type:application/json’ -X PUT --data-binary “body.txt” http://localhost:2113/projection/$by_category/query

But no cigar.