空数据库--修复后台删除issue标签500问题

app/models/tracker.rb

@@ -34,7 +34,7 @@ class Tracker < ActiveRecord::Base
   end
 
   has_and_belongs_to_many :projects
-  has_and_belongs_to_many :courses
+  # has_and_belongs_to_many :courses
   has_and_belongs_to_many :custom_fields, :class_name => 'IssueCustomField', :join_table => "#{table_name_prefix}custom_fields_trackers#{table_name_suffix}", :association_foreign_key => 'custom_field_id'
   acts_as_list