feat: Implement chat functionality

app/Models/Message.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class Message extends Model
+{
+    /** @use HasFactory<\Database\Factories\MessageFactory> */
+    use HasFactory;
+
+    protected $fillable = [
+        'chat_id',
+        'user_id',
+        'content',
+    ];
+
+    public function chat(): BelongsTo
+    {
+        return $this->belongsTo(Chat::class);
+    }
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+}