document Model.pluck usage in :collection option

README.textile

@@ -308,6 +308,9 @@ Many inputs provide a collection of options to choose from (like @:select@, @:ra
   f.input :authors, :as => :check_boxes, :collection => [@justin, @kate]
   f.input :authors, :as => :check_boxes, :collection => ["Justin", "Kate", "Amelia", "Gus", "Meg"]
   f.input :author,  :as => :select,      :collection => Author.all
+  f.input :author,  :as => :select,      :collection => Author.pluck(:first_name, :id)
+  f.input :author,  :as => :select,      :collection => Author.pluck(Arel.sql("CONCAT(`first_name`, ' ', `last_name`)"), :id)
+  f.input :author,  :as => :select,      :collection => Author.your_custom_scope_or_class_method
   f.input :author,  :as => :select,      :collection => { @justin.name => @justin.id, @kate.name => @kate.id }
   f.input :author,  :as => :select,      :collection => ["Justin", "Kate", "Amelia", "Gus", "Meg"]
   f.input :author,  :as => :radio,       :collection => User.all

lib/formtastic/inputs/check_boxes_input.rb

@@ -39,6 +39,7 @@ module Inputs
     #   <%= f.input :categories, :as => :check_boxes, :collection => @categories %>
     #   <%= f.input :categories, :as => :check_boxes, :collection => Category.all %>
     #   <%= f.input :categories, :as => :check_boxes, :collection => Category.some_named_scope %>
+    #   <%= f.input :categories, :as => :check_boxes, :collection => Category.pluck(:label, :id) %>
     #   <%= f.input :categories, :as => :check_boxes, :collection => [Category.find_by_name("Ruby"), Category.find_by_name("Rails")] %>
     #   <%= f.input :categories, :as => :check_boxes, :collection => ["Ruby", "Rails"] %>
     #   <%= f.input :categories, :as => :check_boxes, :collection => [["Ruby", "ruby"], ["Rails", "rails"]] %>

lib/formtastic/inputs/radio_input.rb

@@ -78,6 +78,8 @@ module Inputs
     #   <%= f.input :author, :as => :radio, :collection => @authors %>
     #   <%= f.input :author, :as => :radio, :collection => Author.all %>
     #   <%= f.input :author, :as => :radio, :collection => Author.some_named_scope %>
+    #   <%= f.input :author, :as => :radio, :collection => Author.pluck(:full_name, :id) %>
+    #   <%= f.input :author, :as => :radio, :collection => Author.pluck(Arel.sql("CONCAT(`first_name`, ' ', `last_name`)"), :id)) %>
     #   <%= f.input :author, :as => :radio, :collection => [Author.find_by_login("justin"), Category.find_by_name("kate")] %>
     #   <%= f.input :author, :as => :radio, :collection => ["Justin", "Kate"] %>
     #   <%= f.input :author, :as => :radio, :collection => [["Justin", "justin"], ["Kate", "kate"]] %>

lib/formtastic/inputs/select_input.rb

@@ -94,6 +94,8 @@ module Inputs
     #   <%= f.input :author, :as => :select, :collection => @authors %>
     #   <%= f.input :author, :as => :select, :collection => Author.all %>
     #   <%= f.input :author, :as => :select, :collection => Author.some_named_scope %>
+    #   <%= f.input :author, :as => :select, :collection => Author.pluck(:full_name, :id) %>
+    #   <%= f.input :author, :as => :select, :collection => Author.pluck(Arel.sql("CONCAT(`first_name`, ' ', `last_name`)"), :id)) %>
     #   <%= f.input :author, :as => :select, :collection => [Author.find_by_login("justin"), Category.find_by_name("kate")] %>
     #   <%= f.input :author, :as => :select, :collection => ["Justin", "Kate"] %>
     #   <%= f.input :author, :as => :select, :collection => [["Justin", "justin"], ["Kate", "kate"]] %>