Expand on documentation aimed at server staff

docs/content/staff/logging.md

@@ -0,0 +1,18 @@
+# Proxy logging
+If you want to log every proxied message to a separate channel for moderation purposes, you can use the `pk;log` command with the channel name.For example:
+
+    pk;log #proxy-log
+    
+This requires you to have the *Manage Server* permission on the server. To disable logging, use the `pk;log` command with no channel name.
+
+Log messages have the following format:
+
+![Example log message from PluralKit](../assets/log_example.png)
+
+## Blacklisting channels from logging
+Depending on your server setup, you may want to exclude some messages from logging. For example, if you have public proxy logs, you may want to exclude staff-only channels.
+
+To manage logging in a channel, use the following commands:
+
+    pk;log disable #some-secret-channel
+    pk;log enable #some-secret-channel