Fixes contribution guide and YARD task

Author: Nathan Sutton

CONTRIBUTING.md

@@ -39,7 +39,7 @@ Ideally, a bug report should include a pull request with failing specs.
 7. Run `open coverage/index.html`. If your changes are not completely covered
    by your tests, return to step 3.
 8. Add documentation for your feature or bug fix.
-9. Run `bundle exec rake yard`. If your changes are not 100% documented, go
+9. Run `bundle exec rake doc:yard`. If your changes are not 100% documented, go
    back to step 8.
 10. Add, commit, and push your changes.
 11. [Submit a pull request.][pr]

Rakefile

@@ -10,7 +10,7 @@ task :default => :spec
 namespace :doc do
   require 'yard'
   YARD::Rake::YardocTask.new do |task|
-    task.files   = ['LICENSE.md', 'lib/**/*.rb']
+    task.files   = ['lib/**/*.rb', '-', 'LICENSE.md']
     task.options = [
       '--no-private',
       '--protected',