Added shared mailer package to remove circular dependencies between packages. (#63)

packages/mailers/nodemailer/README.md

@@ -0,0 +1,51 @@
+# Mailers - @kit/mailers
+
+This package is responsible for sending emails using a unified interface across the app.
+
+The default mailer uses the `nodemailer` package to send emails. You can create custom mailers by extending the `Mailer` class.
+
+Make sure the app installs the `@kit/mailers` package before using it.
+
+```json
+{
+    "name": "my-app",
+    "dependencies": {
+        "@kit/mailers": "*"
+    }
+}
+```
+
+## Usage
+
+By default, the package uses `nodemailer`. 
+
+To use [Resend](https:///resend.com)'s HTTP API, please set the environment variable `MAILER_PROVIDER` to `resend`.
+
+```
+MAILER_PROVIDER=resend
+```
+
+### Send an email
+
+```tsx
+import { getMailer } from '@kit/mailers';
+
+async function sendEmail() {
+  const mailer = await getMailer();
+
+  return mailer.sendEmail({
+    to: '',
+    from: '',
+    subject: 'Hello',
+    text: 'Hello, World!'
+  });
+}
+```
+
+## Resend
+
+If you're using the `resend` provider, please add the following environment variables:
+
+```
+RESEND_API_KEY=your-api-key
+```