rails_class_variables

  # Database
  
  add column 'sequence_type_tmp'
  
  # Model
  
  # original is :sequence_type_id (integer) 
  # add :sequence_type_tmp (string)
  
  
  @sequence_types = %w{ protein dna rna }
  @sequence_type_select = [['Protein', 'protein'], ['DNA', 'dna'], ['RNA', 'rna']]
    
    class << self
     attr_accessor :sequence_types, :sequence_type_select
    end
  
  
  # Rake task

  namespace :craic do

  desc "Convert sequence_type_id into sequnce_type"
  task :convert_sequence_type_ids => :environment  do

    Antibody.order('id asc').all.each do |antibody|

      unless antibody.sequence_type.blank?
        antibody.update_attribute(:sequence_type_tmp, antibody.sequence_type.name)
      end
    end

  end

end
    
    
# THEN....
# remove sequence_type_id column
# change sequence_type_tmp column to sequence_type
# update model to use sequence_type instead of sequence_type_tmp
# remove belongs_to sequence_type relation and has_many :antibodies in sequence_type model

  # View  -- form
  
  <%= f.input :sequence_type, :collection => Sequence.sequence_type_select,
      :selected => 'protein' %>