修复打开首页，SQL没有默认的school_id的问题

app/helpers/welcome_helper.rb

@@ -154,11 +154,11 @@ module WelcomeHelper
     sort_course_by_hot limit
   end
 
-  def find_all_new_hot_course limit = 9 ,school_id
+  def find_all_new_hot_course limit = 9 ,school_id = 0
     #sort_project_by_hot_rails 1, 'course_ac_para DESC', limit
     time_now = Time.new.strftime("%Y");
     Project.visible.joins(:project_status).where("#{Project.table_name}.project_type = ? and #{Project.table_name}.created_on like '%#{time_now}%' and #{Project.table_name}.identifier not in
-      (select extra from courses where school_id = #{school_id})", 1).order("course_ac_para DESC").limit(limit).all
+      (select extra from courses where school_id = ?)", 1,school_id).order("course_ac_para DESC").limit(limit).all
   end
 
   def find_all_hot_bid