employee.rb

class Employee < ActiveRecord::Base
  has_many :subordinates, class_name: "Employee", foreign_key: "manager_id"
  belongs_to :manager, class_name: "Employee"

  belongs_to :team 
  has_one :team, foreign_key: "manager_id"
end

schema.rb

create_table "employees", force: :cascade do |t|
    t.string   "name"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer  "manager_id"
    t.integer  "team_id"
  end

  create_table "teams", force: :cascade do |t|
    t.string   "team_name"
    t.integer  "sec_team_id"
    t.datetime "created_at",  null: false
    t.datetime "updated_at",  null: false
    t.integer  "ter_team_id"
    t.integer  "manager_id"
  end

  add_index "teams", ["sec_team_id"], name: "index_teams_on_sec_team_id"

end

team.rb

class Team < ActiveRecord::Base
  #self join within teams
  has_one :teir1, class_name: "Team", foreign_key: "sec_team_id"
  has_one :teir2, class_name: "Team", foreign_key: "ter_team_id"
  belongs_to :sec_team, class_name: "Team"
  belongs_to :ter_team, class_name: "Team"

  #across users
  has_many :subordinates, class_name: "Employee", foreign_key: "subordinate_id"
  belongs_to :manager, class_name: "Employee"
end