Add contestants

app/models/contest.rb

@@ -1,4 +1,5 @@
 class Contest < ApplicationRecord
   belongs_to :user
+  has_many :contestants, dependent: :destroy
   has_many :puzzles, dependent: :destroy
 end

app/models/contestant.rb

@@ -0,0 +1,4 @@
+class Contestant < ApplicationRecord
+  belongs_to :contest
+  validates :name, presence: true
+end