init inbox service with its test

src/Services/Inbox.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace MG\Inbox\Services;
+
+class Inbox
+{
+    public function send($message, $to)
+    {
+        return "Message sent to $to";
+    }
+
+    public function receive($message, $from)
+    {
+        return "Message received from $from";
+    }
+
+    public function markAsRead($message)
+    {
+        return "Message marked as read";
+    }
+
+    public function markAsUnread($message)
+    {
+        return "Message marked as unread";
+    }
+
+    public function delete($message)
+    {
+        return "Message deleted";
+    }
+
+    public function star($message)
+    {
+        return "Message starred";
+    }
+
+    public function unstar($message)
+    {
+        return "Message unstarred";
+    }
+}

tests/Services/InboxTest.php

@@ -0,0 +1,8 @@
+<?php
+
+it('can send a message', function () {
+    $inbox = new \MG\Inbox\Services\Inbox();
+    $result = $inbox->send('Hello', 'Taylor');
+    expect($result)->toBe('Message sent to Taylor');
+});
+