completed story 1.1 with QA tests and fixes

app/Models/Timeline.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Models;
+
+use App\Enums\TimelineStatus;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class Timeline extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'user_id',
+        'case_name',
+        'case_reference',
+        'status',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'status' => TimelineStatus::class,
+        ];
+    }
+
+    /**
+     * Get the user that owns the timeline.
+     */
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    /**
+     * Get the updates for the timeline.
+     */
+    public function updates(): HasMany
+    {
+        return $this->hasMany(TimelineUpdate::class);
+    }
+}