Merge pull request #8333 from amatsuda/rails_gem_empty_require_path

empty rails gem's require_paths

rails.gemspec

@@ -18,6 +18,7 @@
 
   s.bindir      = 'bin'
   s.executables = []
+  s.require_paths = []
   s.files       = Dir['guides/**/*']
 
   s.add_dependency 'activesupport', version