Set site_url when deploying to GitHub Pages

.github/workflows/publish_docs.yml

@@ -1,9 +1,13 @@
 name: Publish Docs 
+
 on:
   push:
     branches:
       - master 
 
+env:
+  HYDRUS_DOCS_SITE_URL: "https://hydrusnetwork.github.io/hydrus/"
+
 jobs:
   deploy:
     runs-on: ubuntu-latest

mkdocs.yml

@@ -1,5 +1,6 @@
 site_name: hydrus network
 site_description: "A personal booru-style media tagger that can import files and tags from your hard drive and popular websites. Content can be shared with other users via user-run servers."
+site_url: !ENV [HYDRUS_DOCS_SITE_URL, '']
 repo_url: https://github.com/hydrusnetwork/hydrus
 repo_name: hydrusnetwork/hydrus
 use_directory_urls: false