Cristian/test check task

we was added celery to this proyect, for it is change them files of settings.py and requeriments.pip. To implement celery, changed the files views.py, task.py and models.py.

In views.py and task.py, created a function that creates the files version in the app, this function  receives 3 parameters, one object of type Resource, other is the code of the version , and the last is the number version of the object.

Also created a function that seeks changes in the websites contained in the database.