Add rubocop default configuration

config/rubocop.yml

@@ -0,0 +1,31 @@
+AllCops:
+  Includes:
+    - '../**/*.rake'
+  Excludes:
+    - '../vendor/**'
+
+# Avoid parameter lists longer than five parameters.
+ParameterLists:
+  Max: 3
+  CountKeywordArgs: true
+
+# Avoid more than `Max` levels of nesting.
+BlockNesting:
+  Max: 3
+
+# Align with the style guide.
+CollectionMethods:
+  PreferredMethods:
+    collect:  'map'
+    inject:   'reduce'
+    find:     'detect'
+    find_all: 'select'
+
+# Do not force public/protected/private keyword to be indented at the same
+# level as the def keyword. My personal preference is to outdent these keywords
+# because I think when scanning code it makes it easier to identify the
+# sections of code and visually separate them. When the keyword is at the same
+# level I think it sort of blends in with the def keywords and makes it harder
+# to scan the code and see where the sections are.
+AccessControl:
+  Enabled: false