File viewer for attached text files.

git-svn-id: http://redmine.rubyforge.org/svn/trunk@1520 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/attachment.rb

@@ -88,6 +88,10 @@ class Attachment < ActiveRecord::Base
     self.filename =~ /\.(jpe?g|gif|png)$/i
   end
   
+  def is_text?
+    Redmine::MimeType.is_type?('text', filename)
+  end
+  
   def is_diff?
     self.filename =~ /\.(patch|diff)$/i
   end