Add cding back down.

Author: eswan18

uc_python/build.py

@@ -8,4 +8,5 @@
     os.chdir(repo)
     print(f"building slides for {repo.name}...")
     run(["make", "slides"], check=True)
-    print("done")
+    print("done")
+    os.chdir("..")

uc_python/collate.py

@@ -4,5 +4,9 @@
 site = Path("site")
 site.mkdir(exist_ok=True)
 
+# Build an index as we go
+index = site / "index.html"
+index.touch()
 for repo in folder.glob("*"):
-    (repo / "slides").rename(site / repo.name)
+    (repo / "slides").rename(site / repo.name)
+    index.write_text(f'<a href="/{repo.name}">{repo.name}</a>')