Add Contributing.MD

CONTRIBUTING.md

@@ -0,0 +1,45 @@
+# Contributing
+
+This project is a monorepo and uses [turborepo](https://turbo.build/repo) as its
+build system with `npm` to manage packages.
+
+## Project Structure
+
+```
+apps
+    |__ front-end
+    |__ collab-server
+
+packages
+    |__ eslint-config
+    |__ typescript-config
+```
+
+`front-end`: The main application powered by Next.js.
+
+`collab-server`: Backend websocket server using HocusPocus and Yjs.
+
+`eslint-config`: Shared ESLint configurations.
+
+`typescript-config`: Shared Typescript configurations.
+
+## Local Development
+
+### Environment Variables
+
+To run the project locally you will need to set up the environment variables.
+
+Take a look at the corresponding `.env.example` file of each application under
+the `/app` directory. Most environment variables are specific to each app
+with the exception of the **auth secret** that is shared across **front-end**
+and **collab-server** to sign and validate JWTs.
+
+Make sure that the value of `NEXTAUTH_SECRET` in front-end matches `AUTH_SECRET`
+in collab-server.
+
+After setting up all the environment variables you can run both projects by
+running:
+
+```
+npm run dev
+```