add options_for_select

add method `options_for_select` from Rails.

Author: wongyouth

Diff for: snippets/eruby.snippets

@@ -107,6 +107,8 @@ snippet ntc
 	<%= number_to_currency(${1}) %>
 snippet ofcfs
 	<%= options_from_collection_for_select ${1:collection}, ${2:value_method}, ${3:text_method}, ${0:selected_value} %>
+snippet ofs
+	<%= options_for_select ${1:collection}, ${2:value_method} %>
 snippet rf
 	<%= render :file => "${1:file}"${0} %>
 snippet rt