feat: Initial commit for Saqel Platform architecture, backend, Docker, and documentation

backend/app/Models/Question.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace App\Models;
+
+use Database\Factories\QuestionFactory;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class Question extends Model
+{
+    /** @use HasFactory<QuestionFactory> */
+    use HasFactory;
+
+    protected $fillable = ['quiz_id', 'concept_id', 'body', 'explanation'];
+
+    public function quiz(): BelongsTo
+    {
+        return $this->belongsTo(Quiz::class);
+    }
+
+    public function concept(): BelongsTo
+    {
+        return $this->belongsTo(Concept::class);
+    }
+
+    public function options(): HasMany
+    {
+        return $this->hasMany(QuestionOption::class);
+    }
+}