Allow slack bot to be reached via DM (#1299)

Author: mcandeia

slack/utils/constants.ts

@@ -8,6 +8,9 @@ export const SCOPES = [
   "app_mentions:read",
   "channels:join",
   "groups:read",
+  "im:history,
+  "im:read",
+  "im:write",
 ];
 
 export const API_URL = "https://slack.com/api";