add option for using a single database

[mxdev88]

This PR implements an option for ScrapydWeb to use a single database. This is useful when used in environement where user does not have the priviliege to create database (e.g. Heroku).

It is assumed the user will not go from one mode to the other (single vs. multiple) and if it is the case, data migration would have to be managed outside the application if need be.

This would allow use cases mentioned in #176, #151 and #139.

[pep8speaks]

Hello @mxdev88! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers:

Comment last updated at 2021-05-16 11:52:39 UTC