adds messaging api controlle for mailgun provider

app/config/services.php

@@ -225,4 +225,17 @@ return [
         'optional' => true,
         'icon' => '/images/services/migrations.png',
     ],
+    'messaging' => [
+        'key' => 'messaging',
+        'name' => 'Messaging',
+        'subtitle' => 'The Messaging service allows you to send messages to any provider type (SMTP, push notification, SMS, etc.).',
+        'description' => '/docs/services/messaging.md',
+        'controller' => 'api/messaging.php',
+        'sdk' => true,
+        'docs' => true,
+        'docsUrl' => 'https://appwrite.io/docs/server/messaging',
+        'tests' => false,
+        'optional' => true,
+        'icon' => '/images/services/messaging.png',
+    ]
 ];

app/controllers/api/messaging.php

@@ -0,0 +1,42 @@
+<?php
+
+use Appwrite\Utopia\Response;
+use Utopia\App;
+use Utopia\Database\Database;
+use Utopia\Database\Document;
+use Utopia\Validator\Text;
+
+/**
+ * Email Providers 
+ */
+App::post('/v1/messaging/providers/mailgun')
+  ->desc('Create Mailgun Provider')
+  ->groups(['api', 'messaging'])
+  ->label('event', 'messages.providers.create')
+  ->label('scope', 'providers.write')
+  ->label('sdk.auth', [APP_AUTH_TYPE_ADMIN])
+  ->label('sdk.namespace', 'messaging')
+  ->label('sdk.description', '/docs/references/messaging/create-provider-mailgun.md')
+  ->label('sdk.response.code', Response::STATUS_CODE_CREATED)
+  ->label('sdk.response.type', Response::CONTENT_TYPE_JSON)
+  ->label('sdk.response.model', Response::MODEL_PROVIDER)
+  ->param('name', '', new Text(128), 'Provider name.')
+  ->param('apiKey', null, new Text(0), 'Mailgun API Key.', true)
+  ->param('domain', null, new Text(0), 'Mailgun Domain.', true)
+  ->inject('dbForProject')
+  ->inject('response')
+  ->action(function (string $name, string $apiKey, string $domain, Database $dbForProject, Response $response) {
+    $provider = $dbForProject->getDocument('providers', '64e33e70dd07f0d03efb');
+    $provider = $dbForProject->createDocument('providers', new Document([
+      'name' => $name,
+      'provider' => 'Mailgun',
+      'type' => 'email',
+      'credentials' => [
+        'apiKey' => $apiKey,
+        'domain' => $domain
+      ],
+    ]));
+    $response
+      ->setStatusCode(Response::STATUS_CODE_CREATED)
+      ->dynamic($provider, Response::MODEL_PROVIDER);
+  });