为主站（www.example.com）设置 discourse，而不是在子域上

[JammyDodger]

I also found this tip really useful to get a letsencrypt certificate working for both www.example.com as well as the example.com address.

Set up Let’s Encrypt with multiple domains / redirects

This is to address the problem where you get certificate errors with any redirects or CNAME DNS entries which point to your actual installed Discourse (sub)domain. If you do not have https configured already (you do if you have done a standard install recently) see Setting up Let’s Encrypt as your first step. There are two patterns that need to be replaced, one ending in --keylength, and another ending in --fullchainpath (in the actual file, your original domain is before each of these switche…