GH-4095 Favorite/Starred Channels (#4222)

webapp/utils/constants.jsx

@@ -54,6 +54,7 @@ export const Preferences = {
     CATEGORY_THEME: 'theme',
     CATEGORY_FLAGGED_POST: 'flagged_post',
     CATEGORY_NOTIFICATIONS: 'notifications',
+    CATEGORY_FAVORITE_CHANNEL: 'favorite_channel',
     EMAIL_INTERVAL: 'email_interval'
 };