feat: Implement chat functionality

app/Models/Mutation.php

@@ -6,6 +6,7 @@ use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphOne;
 
 class Mutation extends Model
 {
@@ -30,4 +31,16 @@ class Mutation extends Model
     {
         return $this->belongsTo(User::class);
     }
+
+    public function chat(): MorphOne
+    {
+        return $this->morphOne(Chat::class, 'chatable');
+    }
+
+    protected static function booted(): void
+    {
+        static::created(function (Mutation $mutation) {
+            $mutation->chat()->create([]);
+        });
+    }
 }