[#2] work on tv series processing

app/Models/Episode.php

@@ -27,4 +27,9 @@ class Episode extends Model
         'show_id',
         'season_id',
     ];
+
+    protected $casts = [
+        'crew' => 'array',
+        'guest_stars' => 'array',
+    ];
 }

app/Models/ExternalId.php

@@ -18,5 +18,8 @@ class ExternalId extends Model
         'facebook_id',
         'instagram_id',
         'twitter_id',
+        'tvdb_id',
+        'freebase_id',
+        'tvrage_id',
     ];
 }

app/Models/Show.php

@@ -45,4 +45,14 @@ class Show extends Model
     {
         return $this->belongsToMany(Person::class, 'show_crew', 'show_id', 'person_id');
     }
+
+    public function images()
+    {
+        return $this->belongsToMany(Image::class, 'show_images', 'show_id', 'image_id');
+    }
+
+    public function videos()
+    {
+        return $this->belongsToMany(Video::class, 'show_videos', 'show_id', 'video_id');
+    }
 }