laravel version 5.0.27 how to rebuild or regenerate composer.json

I have this laravel version 5.0.27 project, it's a live website. It is working without composer.json. Is there any method to generate a valid composer.json for this laravel project? By a valid composer.json, I mean it should contain all the required elements

ie. require,require-dev,autoload, extra, minimum-stability, 

also It should allow me to generate composer.lock file.

So that I can install components easily using composer. I need to work on a functionality in this project, when I tried to create a model using command

 php artisan make:model modelname 

I received this error

  [ErrorException]                                          
  file_get_contents(/var/www/html/myproject/application/composer.json):
  failed to open stream: No such file or directory  

via Chebli Mohamed