style(rubocop): install rubocop configuration

.rubocop.yml

@@ -0,0 +1,35 @@
+inherit_from:
+  - https://dev.k.io/rubocop/rubocop.rails.yml
+
+Style/StringLiterals:
+  EnforcedStyle: double_quotes
+
+Style/WordArray:
+  EnforcedStyle: brackets
+
+Layout/LineLength:
+  Enabled: false
+
+Metrics/AbcSize:
+  Enabled: false
+
+Metrics/BlockLength:
+  Enabled: false
+
+Metrics/ClassLength:
+  Enabled: false
+
+Metrics/CyclomaticComplexity:
+  Enabled: false
+
+Metrics/MethodLength:
+  Enabled: false
+
+Metrics/ModuleLength:
+  Enabled: false
+
+Metrics/PerceivedComplexity:
+  Enabled: false
+
+Lint/MissingSuper:
+  Enabled: false