example.rb

# my_spree_app/config/initializers/qe.rb
module Qe
  # prefix for database tables
  mattr_accessor :table_name_prefix
  self.table_name_prefix ||= 'qe_'
end
  

# my_spree_app/models/some_class.rb
class SomeClass < ActiveRecord::Base
  self.table_name = "#{Qe.table_name_prefix}#{self.table_name}"
  
  # ... model code
end