text: -- +migrate Up
  
  CREATE TABLE application_variable_tmp AS SELECT * FROM application_variable;
  ALTER TABLE application_variable_tmp ADD PRIMARY KEY (id);
  
  ALTER TABLE "application_variable" ADD COLUMN IF NOT EXISTS sig BYTEA;
  ALTER TABLE "application_variable" ADD COLUMN IF NOT EXISTS signer TEXT;
  
  -- +migrate Down
  
  ALTER TABLE "application_variable" DROP COLUMN sig;
  ALTER TABLE "application_variable" DROP COLUMN signer;
  
  UPDATE application_variable 
  SET application_id      = application_variable_tmp.application_id,
      var_name            = application_variable_tmp.var_name,
      var_value           = application_variable_tmp.var_value,
      cipher_value        = application_variable_tmp.cipher_value,
      var_type            = application_variable_tmp.var_type,
  FROM application_variable_tmp
  WHERE application_variable_tmp.id = application_variable.id;
  
  DROP TABLE application_variable_tmp;