在本机上跑，会报 NoMethodError in Devise/sessions#new

 NoMethodError in Devise/sessions#new

Showing /host/Sites/angel_nest/app/views/layouts/application.html.slim where line #18 raised:

undefined method `empty?' for nil:NilClass
  (in /host/Sites/angel_nest/app/assets/stylesheets/application.css.scss)

Extracted source (around line #18):

15:   meta name="author" content="Fred Wu"
16:   meta name="viewport" content="width=device-width, initial-scale=1.0"
17: 
18:   = stylesheet_link_tag :application
19:   = javascript_include_tag :application
20:   = csrf_meta_tags
21: 

非常奇怪，也不知道怎么解决。就是直接从 github clone 下来到……