Add channels to server config

This wasn't being loaded before, now it is.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

omnibot/config.py

@@ -71,6 +71,11 @@ class ServerConfig:
                 )
             self.plugins = obj["plugins"]
 
+        if "channels" in obj:
+            if not isinstance(obj["channels"], Sequence):
+                raise ConfigError("channels", "must by a list of strings")
+            self.channels = obj["channels"]
+
         if "nick" in obj:
             if not isinstance(obj["nick"], str):
                 raise ConfigError("nick", "must be a string")