ntop + Slack integration
------------------------
ntopng can send alerts to slack.com mobile/web-application by means of the slack webhook.

All you need to do is:
1. Go to http://slack.com and create a team


2. Create a few channels. Make sure you use these exact channel names
   #interface
   #host
   #network
   #snmp_device
   #flow
   #mac
   #host_pool

   Each channel will receive notifications about a specific topic

3. Invite people to channels

4. Find on the slack page your webhook
   - Login into Slack
   - Visit https://my.slack.com/services/new/incoming-webhook/
   - Click "Add Incoming WebHooks integration", the channel does not matter
   - Annotate the "Webhook URL"
   - Click "Save", the other settings do not matter

   The Webhook URL should look similar to
   https://hooks.slack.com/services/ZZZZZZZZZZZz/YYYYYYYYY/XXXXXXXXXXXXX

   See https://api.slack.com/tutorials/your-first-slash-command for more details
   about creating your webhook

5. Go to ntopng menu Preferences > Alerts and set
   - Enable slack integration to ON
   - Set a name for the alert sender (e.g. myntopbot)
   - Set the webhook to the value you have found on the previous step

6. Wait until an alert is generated