Updated README.md - Multiple SSL Certs

Added explanation of how to make multiple SSL certs work per Yesod App, which is probably the easier way to deal with the multiple domains on one keter problem.

README.md

@@ -274,6 +274,41 @@ listeners:
     certificate: certificate2.pem
 ```
 
+
+An alternative way to make this possible is adding the following `ssl:` argument
+to the `keter.yaml` file in your Yesod app's `config folder` as follows:
+
+```
+stanzas:
+    - type: webapp
+      exec: ../yourproject
+      ssl:
+        key: /opt/keter/etc/cert/yourproject.key
+        certificate: /opt/keter/etc/cert/yourproject.crt
+        chain-certificates: []
+```
+
+If you don't have your certificates bundled in one `.crt` file, you should add
+the other certificates in the following order
+
+```
+      ssl:
+        [..]
+        chain-certificates:
+          - /opt/keter/etc/middle.crt
+          - /opt/keter/etc/root.crt
+```
+
+This way you can designate certificates per Yesod App while still having one SSL certificate
+in your main `/opt/keter/etc/keter-config.yaml` for your other Yesod apps to default to
+if they don't have this `ssl:` argument in their `config/keter.yaml`.
+
+NOTE: If you get an error that a Bool was expected instead of an Object when adding the `ssl:`
+argument, then for this to work you might need to build Keter from Github, because at the time
+of writing the version of Keter on Hackage does not have this functionality. Just clone or 
+download this repository and build it using stack.
+
+
 ## FAQ
 
 *   Keter spawns multiple failing process when run with `sudo start keter`.