Single Table Inheritance Prototype

Gemfile

source 'https://rubygems.org'

gem 'activerecord'
gem 'pg'
gem 'binding_of_caller'
gem 'pry'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    activemodel (4.0.0)
      activesupport (= 4.0.0)
      builder (~> 3.1.0)
    activerecord (4.0.0)
      activemodel (= 4.0.0)
      activerecord-deprecated_finders (~> 1.0.2)
      activesupport (= 4.0.0)
      arel (~> 4.0.0)
    activerecord-deprecated_finders (1.0.3)
    activesupport (4.0.0)
      i18n (~> 0.6, >= 0.6.4)
      minitest (~> 4.2)
      multi_json (~> 1.3)
      thread_safe (~> 0.1)
      tzinfo (~> 0.3.37)
    arel (4.0.1)
    atomic (1.1.14)
    binding_of_caller (0.7.2)
      debug_inspector (>= 0.0.1)
    builder (3.1.4)
    coderay (1.0.9)
    debug_inspector (0.0.2)
    i18n (0.6.5)
    method_source (0.8.2)
    minitest (4.7.5)
    multi_json (1.8.2)
    pg (0.17.1)
    pry (0.9.12.4)
      coderay (~> 1.0)
      method_source (~> 0.8)
      slop (~> 3.4)
    slop (3.4.6)
    thread_safe (0.1.3)
      atomic
    tzinfo (0.3.38)

PLATFORMS
  ruby

DEPENDENCIES
  activerecord
  binding_of_caller
  pg
  pry

main.rb

require 'rubygems'
require 'bundler/setup'

require 'active_record'
require 'pry'

ActiveRecord::Base.establish_connection(
  adapter: 'postgresql',
  host: 'localhost',
  database: 'sti_development'
)

ActiveRecord::Schema.define do
  if !table_exists? :products
    create_table :products do |t|
      t.string :name
      t.string :type
    end
  end

  if !table_exists? :values
    create_table :values do |t|
      t.float :market
      t.float :buy
      t.float :sell
      t.string :system
    end
  end
end

class Product < ActiveRecord::Base
  belongs_to :value
end

class Value < ActiveRecord::Base
  
end


class AddValueIdToProductsMigration < ActiveRecord::Migration
  def up
    add_column :products, :value_id, :integer
  end
end

AddValueIdToProductsMigration.run(AddValueIdToProductsMigration) if ! Product.column_names.include? :value_id

class Tech1 < Product; end;
class Tech2 < Product; end;
class Tech3 < Product; end;

class Mineral < Product; end;
class Tech2Component < Product; end;
class Tech2CapitalComponent < Product; end;

binding.pry