Added some description to generate actionview gem [ci skip]

actionview/README.rdoc

 = Action View
 
-
-
 == Download and installation
 
 The latest version of Action View can be installed with RubyGems:

actionview/actionview.gemspec

@@ -5,7 +5,7 @@
   s.name        = 'actionview'
   s.version     = version
   s.summary     = 'Rendering framework putting the V in MVC (part of Rails).'
-  s.description = ''
+  s.description = 'Simple, battle-tested conventions and helpers for building web pages.'
 
   s.required_ruby_version = '>= 1.9.3'