Messages to completions conversion

app/models/message.rb

@@ -3,6 +3,8 @@
 # Table name: messages
 #
 #  id           :integer          not null, primary key
+#  author       :string
+#  display_time :string
 #  text         :string           not null
 #  time_seconds :integer          not null
 #  created_at   :datetime         not null
@@ -20,5 +22,6 @@
 class Message < ApplicationRecord
   belongs_to :contest
 
+  validates :author, presence: true
   validates :text, presence: true
 end