add keep active so that the bot would not be displayed as away

This only applies to real user api. For bot user it's not needed.
https://api.slack.com/docs/presence

pytest.ini

@@ -1,2 +1,2 @@
 [pytest]
-addopts = -s -v --doctest-modules --ignore=setup.py
+addopts = -s -v --doctest-modules --ignore=build --ignore=dist --ignore=slackbot.egg-info --ignore=setup.py

slackbot/bot.py

@@ -7,6 +7,8 @@
 import os
 import re
 import sys
+import thread
+import time
 
 from slackbot import settings
 from slackbot.slackclient import SlackClient
@@ -25,9 +27,16 @@ def run(self):
         self._plugins.init_plugins()
         self._dispatcher.start()
         self._client.rtm_connect()
+        thread.start_new_thread(self._keepactive, tuple())
         logger.info('connected to slack RTM api')
         self._dispatcher.loop()
 
+    def _keepactive(self):
+        logger.info('keep active thread started')
+        while True:
+            time.sleep(30 * 60)
+            self._client.ping()
+
 class PluginsManager(object):
     commands = {}