change quotes to work with postgres in addition to sqlite3 and mysql

Signed-off-by: Aissac SRL <istvan.hoka@aissac.ro>

lib/stereotype/pages_controller_extensions.rb

@@ -8,7 +8,7 @@ def self.included(base)
     end
 
     def find_stereotypes
-      @stereotypes = Radiant::Config.find(:all, :conditions => [ "`key` LIKE ?", "stereotype%"]).map(&:key).collect{|k| k.split('.')[1]}.uniq
+      @stereotypes = Radiant::Config.find(:all, :conditions => [ "'key' LIKE ?", "stereotype%"]).map(&:key).collect{|k| k.split('.')[1]}.uniq
     end
   end
 end