Relations in Rails 4.2: 1-to-many or two 1-to-1

Question

How I would describe it should work:

A User Alice can initiate an Exchange with another User Bob. So Alice is the initiating user of this Exchange, and Bob is the requested user.

A User can have many Exchanges.

An Exchange has one initiating_user and one requested_user. I am unsure if this is a 1-to-1 or 1-to-many relationship, since both are of User, but are not addressed with the same name.

An Exchange has exactly two Ratings, but the same problem as before applies. I do not know if this is a 1-to-1 or 1-to-many relationship. Each one of initiating_user and requested_user can make a Rating. Which is then the initiating_user_rating or requested_user_rating respectively.

A Rating belongs to exactly one Exchange.

My Problem:

I am almost certain that there is a much simpler approach than what I am using now, probably just with use of ActiveRecord relations. It works at the moment, but I am not happy with it.

So I guess my questions are:

• Are those initiating_user/requested_user and initiating_user_rating/requested_user_rating relations each 1-to-many or two 1-to-1?
• Is there a better way to set up the relations for this constellation?
• If not, how do I get the structure to be less hacky and more rails-y?

Not-really-UML:

Code:

In app/models/user.rb

# Exchanges
has_many :initiated_exchanges, class_name: "Exchange",
                               foreign_key: "init_user_id"
has_many :requested_exchanges, class_name: "Exchange",
                               foreign_key: "req_user_id"
# Ratings
has_many :init_user_ratings, through: :initiated_exchanges
has_many :req_user_ratings, through: :requested_exchanges

And in app/models/exchange.rb

# Users
belongs_to :init_user, class_name: "User",
                       foreign_key: "init_user_id"
belongs_to :req_user, class_name: "User",
                      foreign_key: "req_user_id"
# Ratings
belongs_to :init_user_rating, class_name: "Rating",
                              foreign_key: "init_user_rating_id"
belongs_to :req_user_rating, class_name: "Rating",
                             foreign_key: "req_user_rating_id"

In app/models/rating.rb

def exchange
  Exchange.find_by("init_user_rating_id=? or req_user_rating_id=?", id, id)
end

From app/db/schema.rb

create_table "exchanges", force: :cascade do |t|
  t.integer  "init_user_id",        null: false
  t.integer  "req_user_id",         null: false
  t.integer  "init_user_rating_id"
  t.integer  "req_user_rating_id"

  t.datetime "created_at",          null: false
  t.datetime "updated_at",          null: false
end

create_table "ratings", force: :cascade do |t|
  t.integer  "rating"
  t.text     "text",                limit: 1000

  t.datetime "created_at",          null: false
  t.datetime "updated_at",          null: false
end