Prevent rake installing incorrect version in app on different rubies

Author: JonRowe

example_app_generator/generate_app.rb

@@ -41,10 +41,12 @@
     |# Rack::Cache 1.3.0 requires Ruby >= 2.0.0
     |gem 'rack-cache', '< 1.3.0' if RUBY_VERSION < '2.0.0'
     |
-    |if RUBY_VERSION >= '1.9.3'
+    |if RUBY_VERSION >= '2.0.0'
     |  gem 'rake', '>= 10.0.0'
+    |elsif RUBY_VERSION >= '1.9.3'
+    |  gem 'rake', '< 12.0.0' # rake 12 requires Ruby 2.0.0 or later
     |else
-    |  gem 'rake', '~> 10.0' # rake 11 requires Ruby 1.9.3 or later
+    |  gem 'rake', '< 11.0.0' # rake 11 requires Ruby 1.9.3 or later
     |end
     |
     |# Version 3 of mime-types 3 requires Ruby 2.0