Implements event submissions over time chart

app/models/call_for_papers.rb

@@ -7,4 +7,20 @@ class CallForPapers < ActiveRecord::Base
   validates_presence_of :start_date, :end_date, :hard_deadline
   validates :rating, :numericality => { :greater_than_or_equal_to => 0, :less_than_or_equal_to => 10 }
 
+  def self.max_weeks
+    all = CallForPapers.all
+    result = [0]
+    all.each do |cfp|
+      result.push(cfp.end_week - cfp.start_week)
+    end
+    result.max
+  end
+
+  def start_week
+    start_date.strftime('%W').to_i
+  end
+
+  def end_week
+    end_date.strftime('%W').to_i
+  end
 end