module Roda::RodaPlugins::ContentFor

def self.configure(app, opts = {})

the :append option to append.
is called multiple times to set data. Overwrite is default, use
Configure whether to append or overwrite if content_for 
def self.configure(app, opts = {})
  app.opts[:append_content_for] = opts.fetch(:append, false)
end

def self.load_dependencies(app, _opts = {})

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