doc: Documentation for Email Testing (#1204)

* Documentation for Email Testing

* Documentation fix

* Fix

doc/contributors/email_testing.md

@@ -0,0 +1,61 @@
+# Local Email Testing
+- The local email testing is done through [MailHog](https://github.com/mailhog/MailHog) which provides email testing through a local email server.
+## Prerequisites
+- Following the general instruction i.e. adding in `volatile/config/config.json`
+   ```json
+    "email": {
+    "host": "localhost",
+    "port": 1025
+    }
+   ```
+- Having MailHog installed in your machine.
+```bash
+# Install MailHog
+wget https://github.com/mailhog/MailHog/releases/download/v1.0.1/MailHog_linux_amd64
+chmod +x MailHog_linux_amd64
+./MailHog_linux_amd64
+```
+- Nodemailer to send email to SMTP server running in your machine.
+   To install nodemailer:
+``` zsh
+npm install nodemailer
+```
+
+## Access Web Interface
+The MailHog UI can be accessed at [http://127.0.0.1:8025/](http://127.0.0.1:8025/).
+All sent emails and their recipients can be viewed here.
+
+## Using Nodemailer to Send Emails via SMTP, which will appear in the MailHog instance.
+- Using nodemailer as the transport method to send emails using SMTP which would be visible in MailHog instance.
+
+```javascript
+import nodemailer from "nodemailer";
+
+const transporter = nodemailer.createTransport({
+    host: "localhost", // SMTP server (MailHog in this case)
+    port: 1025,        // Default MailHog SMTP port
+    secure: false      // No SSL/TLS required
+});
+
+const mailOptions = {
+    from: "no-reply@example.com",
+    to: "test@example.com",
+    subject: "Hello from Nodemailer!",
+    text: "This is a test email sent using Nodemailer."
+};
+
+transporter.sendMail(mailOptions)
+    .then(info => console.log("Email sent:", info.response))
+    .catch(error => console.error("Error:", error));
+```
+- Once the email is sent, you can see it in the MailHog web interface as shown in the screenshot below.
+<img src="image.png" alt="Alt text" width="300" height="200">
+
+## TroubleShooting
+- If the Mailhog is not working :
+```bash
+ps aux | grep MailHog
+#Ensure it is running
+```
+
+