feat: Deadline Functionality

app/Models/Deadline.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class Deadline extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'book_recommendation_id',
+        'deadline',
+        'target_page',
+        'target_chapter',
+    ];
+
+    public function bookRecommendation()
+    {
+        return $this->belongsTo(BookRecommendation::class);
+    }
+    public function userDeadlines()
+    {
+        return $this->hasMany(UserDeadline::class);
+    }
+}