Update nginx.conf to use http_host rather than host fixes #1930
Update nginx.conf to use http_host rather than host fixes #1930

Using proxy_set_header Host $host; does not pass through the port. This causes the /api-doc/ route to miss the port when attempting to render routes. 
This fixes: #1930
inventree/InvenTree,inventree/InvenTree,inventree/InvenTree,SchrodingersGat/InvenTree,SchrodingersGat/InvenTree,SchrodingersGat/InvenTree,inventree/InvenTree,SchrodingersGat/InvenTree