module Roda::RodaPlugins::AdditionalViewDirectories

def self.configure(app, view_dirs)

is also added as an allowed path.
Set the additional view directories to look in. Each additional view directory 
def self.configure(app, view_dirs)
  view_dirs = app.opts[:additional_view_directories] = view_dirs.map{|f| app.expand_path(f, nil)}.freeze
  app.plugin :render, :allowed_paths=>(app.opts[:render][:allowed_paths] + view_dirs).uniq.freeze
end

def self.load_dependencies(app, view_dirs)

sense when the render plugin is used.
Depend on the render plugin, since this plugin only makes 
def self.load_dependencies(app, view_dirs)
  app.plugin :render
end