OOP Installer

[ortegacmanuel]

I saw all the installer changes and besides all they are important, I think we should introduce OOP as a priority. Currently the installer is one long file. It should be a class with different methods and included modules, this way we could organize everything better.

I'm thinking about something like this: https://github.com/thredded/thredded_create_app/blob/master/lib/thredded_create_app/generator.rb#L65

This is highly coupled with all the installer changes and I think it should be a good move before/along with the changes you listed.

[ortegacmanuel]

@acesuares please, let me know what you think about this? please explore this link