docs: update proxy docs

docs/integrations/services/home-assistant/index.md

@@ -25,6 +25,17 @@ This guide requires https://github.com/BeryJu/hass-auth-header, which can be ins
 
 Afterwards, make sure the `trusted_proxies` setting contains the IP(s) of the Host(s) passbook is running on.
 
+With the default Header of `X-Forwarded-Preferred-Username` matching is done on a username basis, so your Name in Home-Assistant and your username in passbook have to match.
+
+If this is not the case, you can simply add an additional header for your user, which contains the Home-Assistant Name and authenticate based on that.
+
+For example add this to your user's properties and set the Header to `X-pb-hass-user`.
+
+```yaml
+additionalHeaders:
+  X-pb-hass-user: some other name
+```
+
 ## passbook
 
 Create a Proxy Provider with the following values

docs/providers/proxy.md

@@ -11,6 +11,14 @@ The Proxy these extra headers to the application:
 
 Header Name | Value
 -------------|-------
-X-Auth-Request-User | The user's unique identifier
+X-Forwarded-User | The user's unique identifier (**not the username**)
-X-Auth-Request-Email | The user's email address
+X-Forwarded-Email | The user's email address
-X-Auth-Request-Preferred-Username | The user's username
+X-Forwarded-Preferred-Username | The user's username
+X-Auth-Username | The user's username
+
+Additionally, you can add more custom headers using `additionalHeaders` in the User or Group Properties, for example
+
+```yaml
+additionalHeaders:
+  X-additional-header: bar
+```