Use case instead of if-elsifs

Closes rubocop#764

README.adoc

@@ -1172,6 +1172,32 @@ result = if some_condition; something else something_else end
 result = some_condition ? something : something_else
 ----
 
+=== `case` vs `if-else` [[case-vs-if-else]]
+
+Prefer `case` over `if-elsif` when compared value is same in each clause.
+
+[source,ruby]
+----
+# bad
+if status == :active
+  perform_action
+elsif status == :inactive || status == :hibernating
+  check_timeout
+else
+  final_action
+end
+
+# good
+case status
+when :active
+  perform_action
+when :inactive, :hibernating
+  check_timeout
+else
+  final_action
+end
+----
+
 === Use `if`/`case` Returns [[use-if-case-returns]]
 
 Leverage the fact that `if` and `case` are expressions which return a result.