make syntax of select.map(&:field) same as pluck

The shortcut ampersand syntax of `select.map(&:field)` is same thing as `.plunk(:field)`. document that
rails · Nov 8, 2012 · e3e4fa1 · e3e4fa1
1 parent 8659212
commit e3e4fa1
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
@@ -1364,6 +1364,8 @@ Client.pluck(:id, :name)
 ```ruby
 Client.select(:id).map { |c| c.id }
 # or
+Client.select(:id).map(&:id)
+# or
 Client.select(:id).map { |c| [c.id, c.name] }
 ```