Allow enabling of Rails Cops in config file

[lawliet89]

I would prefer to do this rather than using the command line argument so that every time I invoke Rubocop, it runs it automatically rather than requiring me to remember to add a -R flag.

[bbatsov]

Seems reasonable. @jonas054 What do you think?

[jonas054]

👍 Agreed. I don't forsee any big problems with adding such a configuration parameter. We just have to be careful so people don't find it confusing. The best way might be to add a parameter like

AllCops:
  RunExtraRailsCops: false

It's false in the default configuration and works just like (and can be overridden by) the --rails command line option.