Update the StatementCache documentation

activerecord/lib/active_record/statement_cache.rb

@@ -1,18 +1,29 @@
 module ActiveRecord
 
   # Statement cache is used to cache a single statement in order to avoid creating the AST again.
-  # Initializing the cache is done by passing the statement in the initialization block:
+  # Initializing the cache is done by passing the statement in the create block:
   #
-  #   cache = ActiveRecord::StatementCache.new do
-  #     Book.where(name: "my book").limit(100)
+  #   cache = StatementCache.create(Book.connection) do |params|
+  #     Book.where(name: "my book").where("author_id > 3")
   #   end
   #
   # The cached statement is executed by using the +execute+ method:
   #
-  #   cache.execute
+  #   cache.execute([], Book, Book.connection)
   #
   # The relation returned by the block is cached, and for each +execute+ call the cached relation gets duped.
   # Database is queried when +to_a+ is called on the relation.
+  #
+  # If you want to cache the statement without the values you can use the +bind+ method of the
+  # block parameter.
+  #
+  #   cache = StatementCache.create(Book.connection) do |params|
+  #     Book.where(name: params.bind)
+  #   end
+  #
+  # And pass the bind values as the first argument of +execute+ call.
+  #
+  #   cache.execute(["my book"], Book, Book.connection)
   class StatementCache # :nodoc:
     class Substitute; end # :nodoc: