git push to dokku fails, database is locked

I just finished the NodeJS / Dokku tutorial at http://www.digitalocean.com/community/articles/how-to-use-the-dokku-one-click-digitalocean-image-to-run-a-node-js-app, and everything worked great. Now, when I edited the demo app.js (added a route) and tried to push it to the server, I get an error about a locked database file.

$ git push dokku master Counting objects: 5, done. Delta compression using up to 4 threads. Compressing objects: 100% (3/3), done. Writing objects: 100% (3/3), 363 bytes | 0 bytes/s, done. Total 3 (delta 2), reused 0 (delta 0) -----> Building pigimon … remote: 2013/12/04 02:55:41 Error: The database file is locked: database is locked To dokku@<ip address>:pigimon ! [remote rejected] master -> master (pre-receive hook declined) error: failed to push some refs to ‘dokku@<ip address>:pigimon’

This command worked fine the first time I used it during the tutorial.

I’ve tried stopping all docker containers, but that didn’t change anything. I searched through the issues for dokku and dokku-pg-plugin, which the demo uses, but found nothing relevant about locked databases. I am new to dokku, Digital Ocean and VPSs in general, and I am not even sure how to start troubleshooting here; if anyone could offer a suggestion about what I should be looking for or what this database is that the error refers to, that would be a big help.