Replace span with a link + href in about.php for credits

.gitignore

@@ -13,10 +13,10 @@ app/storage/logs/*.log
 app/storage/maintenance.flag
 app/storage/cache/*
 !app/storage/cache/.gitkeep
-app/storage/covers/*
-!app/storage/covers/.gitkeep
 app/storage/theses/*
 !app/storage/theses/.gitkeep
+app/storage/banners/*
+!app/storage/banners/.gitkeep
 
 # Nix
 .direnv/