bug: /duck endpoint does not create correct path in the file response field.

[lavirlifiliol]

Actual behaviour

$ curl -L http://quackstack.pythondiscord.com/duck?seed=123
{"file":"http://quackstack.pythondiscord.com/duck?seed=123/static/4f7d04f0501e44f652faa08e8c9dfb12324eea51.png"}
#                                            ^^^^^^^^^^^^^

Expected behaviour

$ curl -L http://quackstack.pythondiscord.com/duck?seed=123
{"file":"http://quackstack.pythondiscord.com/static/4f7d04f0501e44f652faa08e8c9dfb12324eea51.png"}