Implement ticket types priorities and custom fields

app/Models/TicketType.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace App\Models;
+
+use Database\Factories\TicketTypeFactory;
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+#[Fillable(['is_builtin', 'name', 'position', 'project_id', 'system_key'])]
+class TicketType extends Model
+{
+    /**
+     * @var array<int, string>
+     */
+    public const BUILTIN_KEYS = [
+        'task',
+        'parent',
+    ];
+
+    /** @use HasFactory<TicketTypeFactory> */
+    use HasFactory;
+
+    public function project(): BelongsTo
+    {
+        return $this->belongsTo(Project::class);
+    }
+}