nested_class_associations.rb

class District
  has_many   :leagues
  has_many   :seasons, :through => :leagues

  # If this doesn't work
  has_many   :teams, :through => :seasons

  # How about this?
  def teams
    seasons.teams
  end
end

class League
  belongs_to :district
  has_many   :seasons
  has_many   :teams, :through => :seasons
  
end

class Season
  belongs_to :league
  has_many   :teams
  
end

class Team
  belongs_to :season

end