Added hints for basic authentication

FAQ.md

@@ -18,7 +18,7 @@ All settings of Calibre-Web are stored in the app.db in the root folder of the p
 
 I have successfully tested the following OPDS-Readers:
 - Chunky on iOS (mainly for comics)
-- Marvin and Marvin3 on iOS
+- Marvin and Marvin3 on iOS (no longer available in App Store)
 - Calibre-Companion on Android (Book downloads viewing book details are also supported with this reader even it's not using the standard opds features). Download is only working with anonymous browsing enabled
 - Kybook 1/2/3 on iOS
 - Megareader on iOS (download seems not to work)
@@ -32,7 +32,11 @@ I'm not using all the readers regularly, so issues might appear from time to tim
 
 If there is no space to provide your credentials (e.g. in Moon+ Reader) you can add them to the catalogue link (you will need to urlencode any special characters):
 ```
-https://calibre.example.com?auth=username:password
+https://calibre-web.example.com/opds?auth=username:password
+```
+or
+```
+https://username:password@calibre-web.example.com/opds
 ```
 
 
@@ -158,4 +162,4 @@ The comic reader supports currently jpg, jpeg, png, gif (but not animated ones)
 
 ### Which types of Custom columns are supported?
 
-All types of custom columns are supported except the two "Columns Build from other Columns". From the "Long text, like comments..." column only the HTML formatted version is supported.
+All types of custom columns are supported except the two "Columns Build from other Columns". From the "Long text, like comments..." column only the HTML formatted version is supported.