Laravel save image using dropzone.js into MySQL

I'm just trying out dropzone for the first time and would need assistance to set it up. I am getting error 500 thus:

Failed to load resource: the server responded with a status of 500 (Internal Server Error)

This is the controller:

public function storeDocument(Request $request){

         $file = $request->file('file');
         $fileName = uniqid().$file->getClientOriginalName();
         $file->move('gallery/images', $fileName);

         $productVerificationValidation = ProductVerificationValidation::findOrFail($request->productDocumentNameId);
         $documentsUploaded = $productVerificationValidation->productDocumentUpload()->create([
                'gallery_id'    =>  $request->productDocumentNameId,
                'user_id'       =>  Auth::user()->id,
                'company_id'    =>  $request->company_id,
                'product_id'    =>  $request->product_id,
                'file_name'     =>  $fileName,
                'file_size'     =>  $file->getClientSize(),
                'file_mime'     =>  $file->getClientMimeType(),
                'file_path'     =>  'gallery/images'. $fileName
            ]);
    }

This is the route to store the image credentials:

Route::post('product/document/upload/save', array('before'=>'csrf', 'uses'=>'ProductVerificationValidationController@storeDocument'));

This is the form for Dropzone:

<form action="{{url('product/document/upload/save' )}}" 
                        class="dropzone  first-input-div" id="addImages">{{csrf_field()}} 
                        {!!Form::hidden('productDocumentNameId', $productVerificationValidation->id)!!}
                        {!!Form::hidden('product_id', $productVerificationValidation->product_id)!!}
                        {!!Form::hidden('company_id', $productVerificationValidation->company_id)!!}</form>

This is the model setup:

public function productDocumentUpload(){
        return $this->hasMany('App\ProductDocumentUpload');
    }

I'm yet to understand what I need to do right. Please help out.

via Chebli Mohamed