修复课程成员不能编辑、删除、添加的问题

lib/trustie/gitlab/manage_member.rb

@@ -42,12 +42,16 @@ module Trustie
       end
 
       def repository
+        unless project.nil?
           project.repository
         end
+      end
 
       def isGitlabProject?
+        unless repository.nil?
           repository && repository.gitlab?
         end
+      end
 
     end