gistfile1.rb

class CreateBase < ActiveRecord::Migration
  def up
    create_table :games do |t|
      t.integer :home_team_id, :null => false
      t.integer :away_team_id, :null => false
      t.integer :score, :null => false
    end

    create_table :teams do |t|
      t.string :team_name, :null => false
    end
  end
end

# ---------------------------------------------------------------------

class Teams < ActiveRecord::Base
  has_many :away_games, :foreign_key => :away_team_id, :class_name => Games
  has_many :home_games, :foreign_key => :home_team_id, :class_name => Games
end

class Games < ActiveRecord::Base
  belongs_to :home_team, :foreign_key => :home_team_id, :class_name => Teams
  belongs_to :away_team, :foreign_key => :away_team_id, :class_name => Teams
end

# ---------------------------------------------------------------------

Teams.new(:team_name => :foo)
Teams.new(:team_name => :bar)
Games.new(:home_team_id => 1, :away_team_id => 2, :score => 10)

# ---------------------------------------------------------------------

Games.first.away_team # => #<Teams id: 2, team_name: "bar">
Games.first.home_team # => #<Teams id: 1, team_name: "foo">

# ---------------------------------------------------------------------

Teams.first.home_games # => [#<Games id: 1, home_team_id: 1, away_team_id: 2, score: 10>]
Teams.first.away_games # => []

# ---------------------------------------------------------------------

Teams.last.home_games # => []
Teams.last.away_games # => [#<Games id: 1, home_team_id: 1, away_team_id: 2, score: 10>]