def column(name, sql_type = :text, default = nil, null = true)  
      columns << ActiveRecord::ConnectionAdapters::Column.new(name.to_s, default, sql_type.to_s, null)  
    end
def column(name, sql_type = :text, default = nil, null = true)  
      columns << ActiveRecord::ConnectionAdapters::Column.new(name.to_s, default, sql_type.to_s, null)  
    end
Creates an attribute corresponding to a database column.
 N.B No table is created in the database

 == Arguments

 <tt>name</tt>      ::  column name, such as supplier_id in supplier_id int(11).
 <tt>default</tt>   ::  type-casted default value, such as new in sales_stage varchar(20) default 'new'.
 <tt>sql_type</tt>  ::  used to extract the column length, if necessary. For example 60 in company_name varchar(60). null determines if this column allows NULL values.

 == Usage
   class Task < ActiveRecord::Base
     no_table
     column :description,  :text
     column :description,  :string, 'foo', false
   end