Add field to tournament containing playoff_teams_amount

This field represents how many teams advance into playoff stage after
the group stage has ended.

app/controllers/tournaments_controller.rb

@@ -36,6 +36,7 @@ class TournamentsController < ApplicationController
     # create tournament
     tournament = current_user.tournaments.new params
     if group_stage
+      params.require(:playoff_teams_amount)
       groups = organize_teams_in_groups(teams)
       # add groups to tournament
       result = AddGroupStageToTournamentAndSave.call(tournament: tournament, groups: groups)
@@ -103,7 +104,7 @@ class TournamentsController < ApplicationController
   end
 
   def tournament_params
-    params.slice(:name, :description, :public, :teams, :group_stage).permit!
+    params.slice(:name, :description, :public, :teams, :group_stage, :playoff_teams_amount).permit!
   end
 
   def validate_create_params

db/migrate/0000_create_schema.rb

@@ -51,6 +51,7 @@ class CreateSchema < ActiveRecord::Migration[5.2]
       t.string :code, null: false, index: { unique: true }
       t.string :description
       t.boolean :public, default: true
+      t.integer :playoff_teams_amount
 
       # relation to owner
       t.belongs_to :user, index: true, null: false, foreign_key: { on_delete: :cascade }

spec/controllers/tournaments_controller_spec.rb

@@ -121,7 +121,8 @@ RSpec.describe TournamentsController, type: :controller do
         description: Faker::Movies::HarryPotter.quote,
         public: false,
         group_stage: true,
-        teams: teams_with_groups
+        teams: teams_with_groups,
+        playoff_teams_amount: (@teams16.size / 2)
       }
     end
 
@@ -188,6 +189,11 @@ RSpec.describe TournamentsController, type: :controller do
             group_stage = @group_stage_tournament.stages.find_by(level: -1)
             expect(group_stage).to be_a(Stage)
           end
+
+          it 'saves the amount of teams that advance into playoffs' do
+            expect(@group_stage_tournament.playoff_teams_amount)
+              .to eq(create_group_tournament_data[:playoff_teams_amount])
+          end
         end
 
         it 'renders a JSON response with the new tournament' do