MethodError at /customers/5/tasks/new
  undefined method `empty?' for nil:NilClass
Traceback (innermost first)

/home/paul/Projects/stoptime/stoptime.rb: in _form_select
    if opts_list.empty?...
/home/paul/Projects/stoptime/stoptime.rb: in task_form
          _form_select("customer", @customer_list)...
/usr/lib/ruby/1.8/markaby/builder.rb: in instance_eval
      str = instance_eval(&block)...
/usr/lib/ruby/1.8/markaby/builder.rb: in capture
      str = instance_eval(&block)...
/usr/lib/ruby/1.8/markaby/builder.rb: in tag!
        str = capture &block...
(eval): in tag!
/usr/lib/ruby/1.8/markaby/builder.rb: in html_tag
      tag!(sym, *args, &block)...
(eval): in li
/home/paul/Projects/stoptime/stoptime.rb: in task_form
        li do...
/usr/lib/ruby/1.8/markaby/builder.rb: in instance_eval
      str = instance_eval(&block)...
/usr/lib/ruby/1.8/markaby/builder.rb: in capture
      str = instance_eval(&block)...
/usr/lib/ruby/1.8/markaby/builder.rb: in tag!
        str = capture &block...
(eval): in tag!
/usr/lib/ruby/1.8/markaby/builder.rb: in html_tag
      tag!(sym, *args, &block)...
(eval): in ol
/home/paul/Projects/stoptime/stoptime.rb: in task_form