old_contents: from django.contrib.auth.admin import UserAdmin
  from django.contrib.auth.models import User
  from django.contrib import admin
  
  from .models import (
      Project,
      Job,
      Task,
      ProjectWorker,
      UsedTaskTime,
  )
  
  UserAdmin.list_display = (
      'username', 'email', 'first_name', 'last_name',
      'is_active', 'is_superuser', 'is_staff')
  
  admin.site.unregister(User)
  admin.site.register(User, UserAdmin)
  
  
  class ProjectAdmin(admin.ModelAdmin):
      list_display = ('id', 'name', 'start_dt', 'end_dt', 'sortkey')
      list_display_links = ('id', 'name')
      ordering = ['sortkey']
  
  
  admin.site.register(Project, ProjectAdmin)
  
  
  class JobAdmin(admin.ModelAdmin):
      list_display = ('id', 'name', 'sortkey', 'is_vaild')
      list_display_links = ('id', 'name')
      ordering = ['sortkey']
  
      def is_vaild(self, obj):
          return not obj.invalid
      is_vaild.boolean = True
  
  
  admin.site.register(Job, JobAdmin)
  
  
  class TaskAdmin(admin.ModelAdmin):
      list_display = ('id', 'name', 'job', 'sortkey', 'is_vaild')
      list_display_links = ('id', 'name')
      ordering = ['job', 'sortkey']
  
      def is_vaild(self, obj):
          return not obj.invalid
      is_vaild.boolean = True
  
  
  admin.site.register(Task, TaskAdmin)
  
  
  class ProjectWorkerAdmin(admin.ModelAdmin):
      list_display = ('id', 'user', 'project', 'job', 'is_vaild')
      list_filter = ['user', 'project', 'job']
      ordering = ['user', 'project', 'job']
  
      def is_vaild(self, obj):
          return not obj.invalid
      is_vaild.boolean = True
  
  
  admin.site.register(ProjectWorker, ProjectWorkerAdmin)
  
  
  class UsedTaskTimeAdmin(admin.ModelAdmin):
      list_display = ('id', 'taskdate', 'tasktime', 'user', 'project', 'task')
      list_filter = ['user']
      ordering = ['-id']
  
  
  admin.site.register(UsedTaskTime, UsedTaskTimeAdmin)
  
new_contents: from django.contrib.auth.admin import UserAdmin
  from django.contrib.auth.models import User
  from django.contrib import admin
  
  from .models import (
      Project,
      Job,
      Task,
      ProjectWorker,
      UsedTaskTime,
  )
  
  UserAdmin.list_display = (
      'username',
      'email',
      'first_name',
      'last_name',
      'is_active',
      'is_superuser',
      'is_staff',
  )
  
  admin.site.unregister(User)
  admin.site.register(User, UserAdmin)
  
  
  class ProjectAdmin(admin.ModelAdmin):
      list_display = ('id', 'name', 'start_dt', 'end_dt', 'sortkey')
      list_display_links = ('id', 'name')
      ordering = ['sortkey']
      search_fields = ['name']
  
  
  admin.site.register(Project, ProjectAdmin)
  
  
  class JobAdmin(admin.ModelAdmin):
      list_display = ('id', 'name', 'sortkey', 'is_vaild')
      list_display_links = ('id', 'name')
      ordering = ['sortkey']
      search_fields = ['name']
  
      def is_vaild(self, obj):
          return not obj.invalid
      is_vaild.boolean = True
  
  
  admin.site.register(Job, JobAdmin)
  
  
  class TaskAdmin(admin.ModelAdmin):
      list_display = ('id', 'name', 'job', 'sortkey', 'is_vaild')
      list_display_links = ('id', 'name')
      list_filter = ['job']
      search_fields = ['name']
      ordering = ['job', 'sortkey']
  
      def is_vaild(self, obj):
          return not obj.invalid
      is_vaild.boolean = True
  
  
  admin.site.register(Task, TaskAdmin)
  
  
  class ProjectWorkerAdmin(admin.ModelAdmin):
      list_display = ('id', 'user', 'project', 'job', 'is_vaild')
      list_filter = ['user', 'project', 'job']
      ordering = ['user', 'project', 'job']
  
      def is_vaild(self, obj):
          return not obj.invalid
      is_vaild.boolean = True
  
  
  admin.site.register(ProjectWorker, ProjectWorkerAdmin)
  
  
  class UsedTaskTimeAdmin(admin.ModelAdmin):
      list_display = ('id', 'taskdate', 'tasktime', 'user', 'project', 'task')
      list_filter = ['user']
      ordering = ['-id']
  
  
  admin.site.register(UsedTaskTime, UsedTaskTimeAdmin)
  
subject: fix #34. (add filter job on admin task model.)