Fix the where clause in Stats

Now properly show the last 90 days of data instead
of strict quarters.

With the previous code, on the
1st of january, april, july and october, only one
day of data would be shown.

app/controllers/stats_controller.rb

@@ -1,8 +1,9 @@
 class StatsController < ApplicationController
 
   def index
-    procedures = Procedure.where(created_at: Time.current.all_quarter).group("date_trunc('day', created_at)").count
-    dossiers = Dossier.where(created_at: Time.current.all_quarter).group("date_trunc('day', created_at)").count
+    procedures = Procedure.where(:created_at => 90.days.ago..Time.now).group("date_trunc('day', created_at)").count
+    dossiers = Dossier.where(:created_at => 90.days.ago..Time.now).group("date_trunc('day', created_at)").count
+
     @procedures = clean_hash(procedures)
     @dossiers = clean_hash(dossiers)
   end