Prefix docker volumes with application names

This is important so that `docker volume ls` gives useful information.

etc/nixos/services/nextcloud.nix

@@ -6,9 +6,9 @@
       image = "nextcloud:fpm-alpine";
       dependsOn = ["docker-nextcloud-postgres.service"];
       volumes = [
-        "apps:/var/www/html/custom_apps"
-        "config:/var/www/html/config"
-        "data:/var/www/html/data"
+        "nextcloud-apps:/var/www/html/custom_apps"
+        "nextcloud-config:/var/www/html/config"
+        "nextcloud-data:/var/www/html/data"
       ];
       environment = {
         POSTGRES_DB = "nextcloud";

etc/nixos/services/tlaternet.nix

@@ -28,7 +28,7 @@ in
         };
       };
       volumes = [
-        "mail:/srv/mail"
+        "tlaternet-mail:/srv/mail"
       ];
       environment = {
         VIRTUAL_HOST = "tlater.net,www.tlater.net";