add Match model

main-server/app/models/match.rb

@@ -0,0 +1,43 @@
+class Match < ApplicationRecord
+  belongs_to :player1, class_name: "User"
+  belongs_to :player2, class_name: "User"
+
+  enum :status, {
+    ongoing: 0,
+    player1_won: 1,
+    player2_won: 2,
+    draw: 3,
+    abandoned: 4
+  }
+
+  before_validation :assign_uuid, on: :create
+
+  validates :uuid, presence: true, uniqueness: true
+  validates :status, presence: true
+  validates :game_server, presence: true
+  validates :started_at, presence: true
+  validates :duration_seconds, numericality: { only_integer: true, greater_than_or_equal_to: 0 }, allow_nil: true
+  validates :player1_rating_before, :player2_rating_before,
+    presence: true, numericality: { only_integer: true }
+  validates :player1_rating_change, :player2_rating_change,
+    presence: true, numericality: { only_integer: true }
+  validate :players_must_differ
+
+  scope :finished, -> { where.not(finished_at: nil) }
+  scope :for_user, ->(user_or_id) {
+    id = user_or_id.is_a?(User) ? user_or_id.id : user_or_id
+    where(player1_id: id).or(where(player2_id: id))
+  }
+
+  private
+
+  def assign_uuid
+    self.uuid ||= SecureRandom.uuid
+  end
+
+  def players_must_differ
+    if player1_id.present? && player1_id == player2_id
+      errors.add(:player2, "must differ from player1")
+    end
+  end
+end