diff --git a/.gitignore b/.gitignore
index 9e0cbbe..3ccbd54 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 www/
 __pycache__/
 prependnewline.py
+*.tar
diff --git a/convert.py b/convert.py
index 55486cd..f8dfac3 100644
--- a/convert.py
+++ b/convert.py
@@ -5,10 +5,14 @@ from markdown.extensions.wikilinks import WikiLinkExtension
 SOURCE_DIR = Path("docs")       # input folder
 OUTPUT_DIR = Path("www")       # output folder
 
+def my_url_builder(label, base, end):
+    url = (base + label + end).lower().replace(' ', '_')
+    return url
+
 def convert_markdown_to_html(md_path: Path, html_path: Path):
     html_path.parent.mkdir(parents=True, exist_ok=True)
     html = markdown.markdown(md_path.read_text(encoding="utf-8"), extensions=[
-        WikiLinkExtension(base_url='./', end_url='.html'),
+        WikiLinkExtension(base_url='./', end_url='.html', build_url=my_url_builder),
         'tables',
         'fenced_code',
         'sane_lists',