I've encountered this error with ruby-2.2.1 and padrino 0.13.1
$padrino-gen plugin ar_textile
apply https://raw.github.com/padrino/padrino-recipes/master/plugins/ar_textile_plugin.rb
insert Gemfile
insert config/boot.rb
/home/wm/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:457:in `load': No such file to load -- RedCloth (LoadError)
from /home/wm/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:457:in `block in load_file'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:647:in `new_constants_in'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:456:in `load_file'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:354:in `require_or_load'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:317:in `depend_on'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:233:in `require_dependency'
from https://raw.github.com/padrino/padrino-recipes/master/plugins/ar_textile_plugin.rb:18:in `apply'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/actions.rb:223:in `instance_eval'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/actions.rb:223:in `apply'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/padrino-gen-0.13.1/lib/padrino-gen/generators/runner.rb:135:in `execute_runner'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/padrino-gen-0.13.1/lib/padrino-gen/generators/plugin.rb:42:in `setup_plugin'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `block in invoke_all'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `each'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `map'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `invoke_all'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/group.rb:232:in `dispatch'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/padrino-gen-0.13.1/lib/padrino-gen/generators/cli.rb:50:in `setup'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `block in invoke_all'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `each'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `map'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/invocation.rb:133:in `invoke_all'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/group.rb:232:in `dispatch'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
from /home/wm/.rvm/gems/ruby-2.2.1/gems/padrino-gen-0.13.1/bin/padrino-gen:16:in `<top (required)>'
from /home/wm/.rvm/gems/ruby-2.2.1/bin/padrino-gen:23:in `load'
from /home/wm/.rvm/gems/ruby-2.2.1/bin/padrino-gen:23:in `<main>'
I've encountered this error with ruby-2.2.1 and padrino 0.13.1