[pgadmin-support] pgadmin4 running behind nginx

I have installed pgadmin4 on apache 2.2 with mod_wsgi, and it seems to be working correctly. 

The problem is I need to run nginx in front of it to enable https and caching. When I try to access pgadmin with this setup I get errors in the browser about some elements not being able to be loaded because they are linked through http instead of https.

login:1 Mixed Content: The page at 'https://REMOVED-BY-ME/login?next=/browser/browser.css' was loaded over HTTPS, but requested an insecure stylesheet 'http://REMOVED-BY-ME/login?next=%2Fbrowser%2Fbrowser.css'. This request has been blocked; the content must be served over HTTPS.

This is OK at the login page, but once I login, I get the eternal pgadmin is loading screen and a lot more of these same errors in my browser console.

My question is, how can I tell pgadmin4 what its base URL is ?

Thank you.