docs: add authentication section (open-sauced#62)

add authentication section to the docs

docs/contributing/set-up-authentication.md

@@ -0,0 +1,33 @@
+---
+id: set-up-authentication
+title: Set up Authentication
+sidebar_label: Set up Authentication
+keywords:
+  - set up authentication
+---
+
+To interact with the OpenSauced public API as an authenticated user, you need to obtain an authentication token.
+The following steps outline how to obtain an authentication token from the [hot.opensauced.pizza](https://hot.opensauced.pizza) website:
+
+1. Click on your avatar in the top right corner of the page. This will open a dropdown menu.
+
+   ![Avatar in top right corner of the page](../../static/img/contributing-avatar-top-right.png)
+
+2. Click on the **Print Auth Token** option. Don't worry, this is a safe operation. The token is only printed to the console.
+
+   ![Print Auth Token](../../static/img/contributing-print-auth-token.png)
+
+3. Copy the token that is printed to the console.
+
+   ![Token printed to the console](../../static/img/contributing-token-printed-to-console.png)
+
+4. You can now use this token to make authenticated requests to the OpenSauced public API by including it in the Authorization header of your requests. For example:
+
+   ```javascript
+   const response = await fetch("https://api.opensauced.pizza/v1/auth/session", {
+     method: "GET",
+     headers: {
+       Authorization: `Bearer ${token}`,
+     },
+   });
+   ```

sidebars.js

@@ -20,6 +20,7 @@ module.exports = {
         'contributing/introduction-to-contributing',
         'contributing/code-of-conduct',
         'contributing/triage-guide',
+        'contributing/set-up-authentication'
       ],
     },
     {