Add API support for querying admin reports by date range

app/models/email_log.rb

@@ -13,8 +13,8 @@ class EmailLog < ActiveRecord::Base
     User.where(id: user_id).update_all("last_emailed_at = CURRENT_TIMESTAMP") if user_id.present? and !skipped
   end
 
-  def self.count_per_day(sinceDaysAgo = 30)
-    where('created_at > ? and skipped = false', sinceDaysAgo.days.ago).group('date(created_at)').order('date(created_at)').count
+  def self.count_per_day(start_date, end_date)
+    where('created_at >= ? and created_at < ? AND skipped = false', start_date, end_date).group('date(created_at)').order('date(created_at)').count
   end
 
   def self.for(reply_key)
@@ -22,8 +22,7 @@ class EmailLog < ActiveRecord::Base
   end
 
   def self.last_sent_email_address
-    where(email_type: 'signup').order('created_at DESC')
-                               .first.try(:to_address)
+    where(email_type: 'signup').order('created_at DESC').first.try(:to_address)
   end
 
 end