Public scoreboard stopwatch feature

#10

app/models/contest.rb

@@ -10,9 +10,12 @@
 #  lang               :string           default("en")
 #  name               :string
 #  offline_form       :boolean          default(FALSE)
+#  pause_time         :datetime
 #  public             :boolean          default(FALSE)
 #  ranking_mode       :string
+#  show_stopwatch     :boolean
 #  slug               :string
+#  start_time         :datetime
 #  team               :boolean          default(FALSE)
 #  created_at         :datetime         not null
 #  updated_at         :datetime         not null