feat: Add terminal screenshots for Ruby quickstart

- Add keploy record screenshot
- Add API test generation screenshot
- Add keploy test screenshot
- Copy images to static/img/sinatra-postgres/

Signed-off-by: Atul Chahar <atul.chahar.0410@gmail.com>

Author: Atul Chahar

static/img/sinatra-postgres/generate-testcases-sinatra.png

@@ -51,6 +51,8 @@ Capture the test cases:
 keploy record -c "docker compose up" --container-name "sinatra-app" --buildDelay 50
 ```
 
+![Keploy Record Sinatra](/img/sinatra-postgres/keploy-record-sinatra.png)
+
 🔥 **Make some API calls**. Postman, Hoppscotch, or even curl - take your pick!
 
 ### Generate testcases
@@ -97,6 +99,8 @@ curl http://localhost:4567/users/1
 curl -X DELETE http://localhost:4567/users/2
 ```
 
+![Generate Testcases Sinatra](/img/sinatra-postgres/generate-testcases-sinatra.png)
+
 And once you are done, you can stop the recording and give yourself a pat on the back! With that simple spell, you've conjured up test cases with mocks! Explore the **keploy** directory and you'll discover your handiwork in `tests` directory and `mocks.yml`.
 
 ### Time to run the testcases 🏃
@@ -105,6 +109,8 @@ And once you are done, you can stop the recording and give yourself a pat on the
 keploy test -c "docker compose up" --containerName "sinatra-app" --delay 10
 ```
 
+![Keploy Test Sinatra](/img/sinatra-postgres/keploy-test-sinatra.png)
+
 You can also check the test summary from your CLI.
 
 ## Running App Locally on Linux/WSL 🐧