Add bet model

* has_many relations in all belonging models
* specs for relations in existing models
* association specs for bet model

app/models/bet.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Bet < ApplicationRecord
+  belongs_to :user
+  belongs_to :match
+  belongs_to :team, optional: true
+end

app/models/match.rb

@@ -5,7 +5,9 @@ class Match < ApplicationRecord
 
   belongs_to :stage, optional: true
   belongs_to :group, optional: true
+
   has_many :match_scores, dependent: :destroy
+  has_many :bets, dependent: :destroy
 
   validates :match_scores, length: { maximum: 2 }
 

app/models/team.rb

@@ -4,6 +4,7 @@ class Team < ApplicationRecord
   belongs_to :tournament, optional: true
   has_many :group_scores, dependent: :destroy
   has_many :match_scores, dependent: :destroy
+  has_many :bets, dependent: :destroy
 
   validates :name, presence: true
 

app/models/user.rb

@@ -11,4 +11,5 @@ class User < ApplicationRecord
   validates :username, presence: true, uniqueness: { case_sensitive: false }
 
   has_many :tournaments, dependent: :destroy
+  has_many :bets, dependent: :destroy
 end

db/migrate/0001_create_bets.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class CreateBets < ActiveRecord::Migration[5.2]
+  def change
+    create_table :bets do |t|
+      t.references :user, index: true, null: false, foreign_key: { on_delete: :cascade }
+      t.references :match, index: true, null: false, foreign_key: { on_delete: :cascade }
+      t.references :team, index: true, null: true, foreign_key: { on_delete: :cascade }
+
+      t.timestamps
+    end
+  end
+end

spec/models/bet_spec.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Bet, type: :model do
+  describe 'association' do
+    it { should belong_to :user }
+    it { should belong_to :match }
+    it { should belong_to(:team).optional }
+  end
+end

spec/models/match_spec.rb

@@ -5,6 +5,7 @@ require 'rails_helper'
 RSpec.describe Match, type: :model do
   context 'association' do
     it { should have_many :match_scores }
+    it { should have_many :bets }
     it { should belong_to(:stage).optional }
     it { should belong_to(:group).optional }
   end

spec/models/team_spec.rb

@@ -11,5 +11,6 @@ RSpec.describe Team, type: :model do
     it { should belong_to(:tournament).optional }
     it { should have_many :group_scores }
     it { should have_many :match_scores }
+    it { should have_many :bets }
   end
 end

spec/models/user_spec.rb

@@ -5,6 +5,7 @@ require 'rails_helper'
 RSpec.describe User, type: :model do
   describe 'association' do
     it { should have_many :tournaments }
+    it { should have_many :bets }
   end
 
   describe 'validation' do