Convert Services to Singleton

app/services/group_stage_service.rb

@@ -1,6 +1,9 @@
 # frozen_string_literal: true
+require 'singleton'
 
 class GroupStageService
+  include Singleton
+
   def self.generate_group_stage(groups)
     raise 'Cannot generate group stage without groups' if groups.length.zero?
 

app/services/match_service.rb

@@ -1,6 +1,9 @@
 # frozen_string_literal: true
+require 'singleton'
 
 class MatchService
+  include Singleton
+
   # Generates all necessary matches from a list of teams
   #
   # @param teams [Array] the teams to generate matches with

app/services/playoff_stage_service.rb

@@ -1,6 +1,9 @@
 # frozen_string_literal: true
+require 'singleton'
 
 class PlayoffStageService
+  include Singleton
+
   # Generates the playoff stage given the tournament
   #
   # @param teams [Array] The teams to generate the playoff stages with

app/services/utils.rb

@@ -1,6 +1,9 @@
 # frozen_string_literal: true
+require 'singleton'
 
 class Utils
+  include Singleton
+
   # Calculates the previous power of 2 given a number
   #
   # @param number [Integer] the number to generate the previous power of 2 from