Show channel announcements from slack channels

[BonfaceKilz]

As a biohackathon participant, I want to be able to view channel announcements and other important news from Slack so that I can stay informed without having to be inside Slack

Feature: Add slack feed]
For this, only a working a demo will be shown. Later when I present the project to people, folks will choose what channels I should scrape

Scenario:
Given a user clicks on the Slack Tab
When he/ she loads the feed page
Then the latest announcements from the various channels are shown