message: Slack example - add instructions on how to setup the Slack App
diff: @@ -4,6 +4,17 @@ const app = new Reshuffle()
  // Reshuffle Slack connector documentation: https://github.com/reshufflehq/reshuffle-slack-connector
  +/**
  +This connector required a Slack App to be configured:
  + - Go to https://api.slack.com/apps
  + - Click on `Create New App`
  +- Enter a `name` and select a `workspace`
  +- Click on `Create App`
  +- Click on your new app
  +- The signing secret is under `Basic Information` > `App Credentials`
  +- The token is under `Settings` > `Install App` > OAuth Access Token
  +*/
  +
  const main = async () => {
  // Create a new Slack Connector: Token and signingSecret are found at https://api.slack.com/apps/<your_slack_app_id>/event-subscriptions
  const slackConnector = new SlackConnector(app, {
  @@ -13,10 +24,11 @@ const main = async () => {
  endpoints: '<slack_receiver_endpoints>', // Default to '/'
  })
  - /** How to setup events in Slack: https://api.slack.com/apps/<your_slack_app_id>/event-subscriptions
  - 1 - Change request URL to <your_runtime_url>:<slack_receiver_port>/<slack_receiver_endpoints>
  - 2 - Subscribe to bot events. For example 'message.channels' for notifying Reshuffle when a new message was posted to a channel
  - 3 - In Reshuffle, use the correct SlackEvents (e.g. SlackEvents.MESSAGE in example below)
  + /** How to setup events in Slack:
  + 1 - Go to https://api.slack.com/apps/<your_slack_app_id>/event-subscriptions
  + 2 - Change request URL to <your_runtime_url>:<slack_receiver_port>/<slack_receiver_endpoints>
  + 3 - Subscribe to bot events. For example 'message.channels' for notifying Reshuffle when a new message was posted to a channel
  + 4 - In Reshuffle, use the correct SlackEvents (e.g. SlackEvents.MESSAGE in example below)
  Full list of Slack events type that Reshuffle can listen to: https://api.slack.com/events
  Full list of Reshuffle constants mapping to Slack events type: https://github.com/reshufflehq/reshuffle-slack-connector/blob/master/src/SlackEvents.ts)
  @@ -29,7 +41,7 @@ const main = async () => {
  },
  },
  (event) => {
  - const payload = event.context.payload
  + const payload = event.payload
  console.log(
  `Slack - message event detected [channel: ${payload.channel}, type: ${payload.type}, subtype: ${payload.subtype}]!`,
  )
  