updated postman screenshots to use JSON instead of query params

Author: Mikelle Wade

ada-project-docs/assets/postman_feature.png

@@ -130,11 +130,12 @@ Open Postman and make a request that mimics the API call to Slack that we just t
 
 - Change the method to `POST`
 - Use this as the request URL: `https://slack.com/api/chat.postMessage`
-- In "Params," fill in the following values:
+- In "Body", select "raw" then change the content-type from "Text" to JSON.
+- After, fill in the following key/value pairs:
   - `channel`: `task-notifications`
   - `text`: Fill in a nice message
 
-![](assets/postman_test_query_params.png)
+![](assets/postman_test_JSON.png)
 
 - In "Headers," add this new key-value pair:
   - `Authorization`: `"Bearer xoxb-150..."`, where `xoxb-150...` is your full Slackbot token