ValidYoutubeVideo Rule (#145)

* ValidYoutubeVideo Rule

* Removed extra accidental line

* Update ValidYoutubeVideo.php

* Delete .gitignore

* Revert "Delete .gitignore"

This reverts commit 0e78d94.

* Only request video id

* Restore .gitignore to master original

* Revert "Restore .gitignore to master original"

This reverts commit ff7eced.

* Update .gitignore

* Update README.md

README.md

@@ -117,6 +117,20 @@ $videoId = Youtube::parseVidFromURL('https://www.youtube.com/watch?v=moSFlvxnbgk
 // result: moSFlvxnbgk
 ```
 
+## Validation Rules
+
+```php
+// use Alaouy\Youtube\Rules\ValidYoutubeVideo;
+
+
+// Validate a YouTube Video URL
+[
+    'youtube_video_url' => ['bail', 'required', new ValidYoutubeVideo]
+];
+```
+
+You can use the bail rule in conjunction with this in order to prevent unnecessary queries.  
+
 ## Basic Search Pagination
 
 ```php

src/Rules/ValidYoutubeVideo.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace Alaouy\Youtube\Rules;
+
+use Illuminate\Contracts\Validation\Rule;
+use Alaouy\Youtube\Facades\Youtube;
+
+class ValidYoutubeVideo implements Rule
+{
+    /**
+     * Create a new rule instance.
+     *
+     * @return void
+     */
+    public function __construct()
+    {
+        //
+    }
+
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @return bool
+     */
+    public function passes($attribute, $value)
+    {
+        try {
+            $videoId = Youtube::parseVidFromURL($value);
+            $video = Youtube::getVideoInfo($videoId, ['id']);
+        } catch (\Exception $exception) {
+            return false;
+        }
+
+        return $video != false;
+    }
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message()
+    {
+        return 'The supplied URL does not look like a Youtube URL.';
+    }
+}