Use format_html instead of plain text

app/admin.py

@@ -1,4 +1,5 @@
 from django.contrib import admin
+from django.utils.html import format_html
 from .models import *
 
 
@@ -76,7 +77,8 @@ class ResourceAdmin(admin.ModelAdmin):
     # )
 
     def resource_url(self, instance):
-        return '<a href="%s" target="_blank">%s</a>' % (str(instance.url).strip("#"), str(instance.url).strip("#"))
+        return format_html('<a href="{0}" target="_blank">{1}</a>',
+                           str(instance.url).strip("#"), str(instance.url).strip("#"))
 
 
 class RangeAdmin(admin.ModelAdmin):