fixes Report#to_params. we now return filters that can be selected in the ui, only

lib/report.rb

@@ -51,14 +51,15 @@ class Report < ActiveRecord::Base
 
   # Convenience method to generate a params hash readable by Controller#determine_settings
   def to_params
-    params = { :fields => [], :operators => {}, :values => {}, :groups => { :rows => [], :columns => [] } }
-    filters.each do |f|
+    params = {}
+    filters.select { |f| f.class.display? }.each do |f|
       filter_name = f.class.underscore_name
       params[:fields] << filter_name
       params[:operators].merge! filter_name => f.operator.to_s
       params[:values].merge! filter_name => f.values
     end
     group_bys.each do |g|
+      params[:groups] ||= { :rows => [], :columns => [] }
       params[:groups][g.row? ? :rows : :columns] << g.class.underscore_name
     end
     params