[#50] Read rubockop config from file

We have introduced a possibility to read rubocop configuration from file. From now on, defining which triggers need to
fired can be also defined from the repository level. You just need to provide proper attributes in config/rubocop/
directory
Merge pull request #58 from X8/50-read_rubocop_config_from_file

[#50] Read rubocop config from file