filters.py: Filter required users

If RESP_ONLY_REQ_USERS configuration is true,
then stop responding to users other than those
in the REQUIRED_USERS list in config.

Closes #515

config.py

@@ -87,6 +87,10 @@
 IGNORE_USERNAMES = os.environ.get("IGNORE_USERNAMES",
                                   'co-robo coala-bot').split()
 
+RESP_ONLY_REQ_USERS = False
+
+REQUIRED_USERS = []
+
 DIVERT_TO_PRIVATE = ('help', )
 
 ROOMS_TO_JOIN = (

utils/filters.py

@@ -23,7 +23,10 @@ def filters(self, msg, cmd, args, dry_run):
         return msg, cmd, args
 
     @cmdfilter
-    def filter_ignored_users(self, msg, cmd, args, dry_run):
+    def filter_users(self, msg, cmd, args, dry_run):
         if msg.frm.nick in self.bot_config.IGNORE_USERNAMES:
             return None, None, None
+        if (msg.frm.nick not in self.bot_config.REQUIRED_USERS and
+               self.bot_config.RESP_ONLY_REQ_USER):
+            return None, None, None
         return msg, cmd, args