My rubocop config

.rubocop.yml

AllCops:
  DisplayStyleGuide: true
  ExtraDetails: true
  UseCache: false
  Exclude:
    # These files are generated automaticaly
    - 'bin/**/*'
    - "db/schema.rb"

# I think 80 is kinda obsolete. Nowdays we can easily read 120+ chars
# But of course you should make your lines as short as possible,
# I just dont see a reason why we should set max at 80.
#
# [Here](https://github.com/bbatsov/ruby-style-guide/issues/207)
# people suggest to set it to 100
Metrics/LineLength:
  Max: 120
  # To make it possible to copy or click on URIs in the code, we allow lines
  # contaning a URI to be longer than Max.
  AllowURI: true
  URISchemes:
    - http
    - https

Metrics/BlockLength:
  Exclude:
    # Specs can be pretty large in terms of block length
    - 'spec/**/*'

# I think in some cases 20-30 lines are ok
# but in these cases you can just disable this cop in place
Metrics/MethodLength:
  Max: 15
  CountComments: false

# Maybe it's a good idea to to exclude
# controllers and helpers too
Style/Documentation:
  Exclude:
    - 'db/**/*'

Rails:
  Enabled: true

# I presume that code under the lib/
# is not rails-specific
Rails/Delegate:
  Exclude:
    - 'lib/**/*'

# In case you have thin models
# I suggest to disable this cop completely
Rails/SkipsModelValidations:
  Exclude:
    - 'db/migrate/**/*'
    - 'spec/**/*'

# I don't see why we should reject using unix syntax.
# How the hell many people runs code on system where
# slash is not a separator?
# For what it worth, it's just more readable
# so I think this cop should be enabled only in few cases
Rails/FilePath:
  Enabled: false