Improve admin interfaces.

mayan/apps/document_comments/admin.py

@@ -5,10 +5,10 @@ from django.contrib import admin
 from .models import Comment
 
 
+@admin.register(Comment)
 class CommentAdmin(admin.ModelAdmin):
     date_hierarchy = 'submit_date'
     list_display = ('document', 'submit_date', 'user', 'comment')
+    list_filter = ('user',)
     readonly_fields = ('document', 'submit_date', 'user', 'comment')
-
-
-admin.site.register(Comment, CommentAdmin)
+    search_fields = ('comment',)