module Roda::RodaPlugins::ErrorMail

def self.configure(app, opts=OPTS)

Set default opts for plugin. See ErrorEmail module RDoc for options. 
def self.configure(app, opts=OPTS)
  app.opts[:error_mail] = email_opts = (app.opts[:error_mail] || OPTS).merge(opts).freeze
  unless email_opts[:to] && email_opts[:from]
    raise RodaError, "must provide :to and :from options to error_mail plugin"
  end
end