Merge pull request #14 from finnlabs/feature/rails3_sti

Feature/rails3 sti

lib/report/filter/base.rb

@@ -170,8 +170,6 @@ class Report::Filter
     end
 
     def initialize(child = nil, options = {})
-      # TODO: wtf?
-      #raise ArgumentError, "Child has to be a Filter." if child and not child.filter?
       @values = []
       super
     end

lib/report/sql_statement.rb

@@ -142,7 +142,7 @@ class Report::SqlStatement
     join_syntax = "LEFT OUTER JOIN %1$s ON %1$s.id = %2$s_id"
     list.each do |e|
       case e
-      when Class          then joins << (join_syntax % [table_name_for(e), e.model_name.underscore])
+      when Class          then joins << (join_syntax % [table_name_for(e), e.lookup_ancestors.last.model_name.underscore])
       when / /            then joins << e
       when Symbol, String then joins << (join_syntax % [table_name_for(e), e])
       when Hash           then e.each { |k,v| joins << (join_syntax % [table_name_for(k), field_name_for(v)]) }