simplify upload file using multiparty to the server

## Installation

```bash
package.json

{
    "dependencies": {
        "media_upload":"*"
    }
}

$ npm install
```

## configuration.json
```js
{
     "upload_to": "/home/images/",
     "public_url":"http://localhost/images/"
}
```

## Use it

```js
var media_upload = require("media_upload");
media_upload.upload_file(req, function(error, file_url){
    console.log(file_url);
});
```