Add resizable traits

[handiwijoyo]

This traits will allow us to use thumbnail helper to generate image url when using Image additional fields. See: https://voyager.readme.io/docs/additional-field-options#section-image

Example of use:

use TCG\Voyager\Traits\Resizable;

class Post extends Model
{
    use Resizable;
}

Use it on view (usually on your site frontend):

@foreach($posts as $post)
    {{$post->thumbnail('small')}}
@endforeach

Or you can specify the optional image field name (attribute), default to image

@foreach($posts as $post)
    {{$post->thumbnail('small', 'photo')}}
@endforeach

[fletch3555]

@handiwijoyo, would you mind updating the docs for this?

[handiwijoyo]

@fletch3555 I think we need to add new Helpers section in the docs, that will document all of available helpers function

[fletch3555]

I'm inclined to agree. I'll create the page later today if you'd like to suggest edits for it. Not sure if I can give you access to Readme.io, but if so, I'll do that instead

[def-media]

Please consider replacing "rtrim" function.

I had the next situation:
$name = rtrim('posts/January2018/OLJEeEfdQi4mI7Cgbhae.jpeg', '.jpeg')
which returns
"posts/January2018/OLJEeEfdQi4mI7Cgbha"
(missing the last "e" character in the string).

It seems like "rtrim" also removes the last character of the file name if that character is present in the file exstension.

I suggest replacing:
$name = rtrim($image, '.'.$ext);
with
$name = \Illuminate\Support\Str::replaceLast('.'.$ext, '', $image); .

It works in my case.