Add contest duration & complete ranking mode implementation

app/models/contest.rb

@@ -4,6 +4,8 @@
 #
 #  id                 :integer          not null, primary key
 #  allow_registration :boolean          default(FALSE)
+#  duration           :string
+#  duration_seconds   :integer
 #  lang               :string           default("en")
 #  name               :string
 #  offline_form       :boolean          default(FALSE)
@@ -37,9 +39,19 @@ class Contest < ApplicationRecord
 
   friendly_id :name, use: :slugged
 
+  before_save :add_duration_seconds
+
   validates :name, presence: true
   validates :lang, inclusion: { in: Languages::AVAILABLE_LANGUAGES.map { |lang| lang[:id] } }
   validates :ranking_mode, inclusion: { in: Ranking::AVAILABLE_RANKING_MODES.map { |lang| lang[:id] } }
+  validates :duration, format: { with: /\A(\d\d:\d\d|\d:\d\d)\z/ }
 
   generates_token_for :token
+
+  def add_duration_seconds
+    arr = self.duration.split(":")
+    if arr.size == 2
+      self.duration_seconds = arr[0].to_i * 3600 + arr[1].to_i * 60
+    end
+  end
 end