some progress

app/Models/MovieCollection.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class MovieCollection extends Model
+{
+    protected $fillable = [
+        'name',
+        'slug',
+        'poster_path',
+        'backdrop_path',
+        'tmdb_id',
+    ];
+
+    public function movies() {
+        return $this->belongsToMany(Movie::class, 'movies_in_collection', 'collection_id', 'movie_id');
+    }
+}