Creating participant_id column

[ameghana]

Please set the title of your pull request in the following format: [Project id/Independent study/Issue fix/...]. project name, eg., E904. Integrating courses and assignments on Expertiza with Moodle

We suggest you including the below information in your pull request:

• A description of the changes proposed in the pull request.
• @mentions of the person or team responsible for reviewing proposed changes.

---

About the Expertiza Bot

• If you have any questions about comments given by the expertiza-bot (example), you could create a new comment in your pull request with the content /dispute [UUID1] [UUID2] (example), then the professor and TAs will be notified.
• Here is a video about how to communicate to the expertiza-bot.