Post to Slack (#603)

* Migrations

* WIP: Integration model, slack perms / hooks

* So so rough it pains me. Building this new model is revealing just how much needs to be refactored

* Working connect and post

* Cleanup UI, upating documents

* Show when slack command is connected

* stash

* 💚

* Add documents.update trigger

* Authorization, tidying

* Fixed integration policy

* pick integration presenter keys

app/scenes/Settings/components/SlackButton.js

@@ -1,5 +1,5 @@
 // @flow
-import React from 'react';
+import * as React from 'react';
 import styled from 'styled-components';
 import { inject } from 'mobx-react';
 import { slackAuth } from 'shared/utils/routeHelpers';
@@ -11,19 +11,27 @@ type Props = {
   auth: AuthStore,
   scopes?: string[],
   redirectUri?: string,
+  state?: string,
+  label?: string,
 };
 
-function SlackButton({ auth, scopes, redirectUri }: Props) {
+function SlackButton({ auth, state, label, scopes, redirectUri }: Props) {
   const handleClick = () =>
     (window.location.href = slackAuth(
-      auth.getOauthState(),
+      state ? auth.saveOauthState(state) : auth.genOauthState(),
       scopes,
       redirectUri
     ));
 
   return (
     <Button onClick={handleClick} icon={<SpacedSlackLogo size={24} />} neutral>
-      Add to <strong>Slack</strong>
+      {label ? (
+        label
+      ) : (
+        <span>
+          Add to <strong>Slack</strong>
+        </span>
+      )}
     </Button>
   );
 }