Create realistic number of Matches

When match_count is -1 the number of matches generated is automatically
2 ^ stage.level -> This is the amount of stages present in a "real"
tournament stage. When supplying a positive number, it generates that
many matches like before.

This also now adds the position to the match list after creating them

spec/factories/stages.rb

@@ -19,7 +19,10 @@ FactoryBot.define do
         match_count { 4 }
       end
       after(:create) do |stage, evaluator|
-        stage.matches = create_list(:match, evaluator.match_count)
+        # match_count -1 automatically generates 2 ^ stage.level matches
+        # (as this would be the amount of stages present in the real world)
+        stage.matches = create_list(:match, evaluator.match_count == -1 ? 2**stage.level : evaluator.match_count)
+        stage.matches.each_with_index { |match, i| match.position = i }
       end
     end
   end