Create the code-submitter database if missing

This ensures that the database can be re-created if it's been
removed (as we do between SR years), even if the code hasn't changed.

Fixes #58.

roles/code-submitter/tasks/main.yml

@@ -76,6 +76,11 @@
   notify:
     Reload nginx
 
+- name: Check if database exists
+  shell: test -f "{{ install_dir }}/sqlite.db" || echo "Missing"
+  register: detect_database
+  changed_when: detect_database.stdout.startswith("Missing")
+
 - name: Install database  # noqa: no-changed-when - We want to always run this (it handles its own idempotency)
   shell:  # noqa: command-instead-of-shell - We need this to use `environment`
     argv:
@@ -86,7 +91,7 @@
   environment:
     PYTHONPATH: "{{ install_dir }}"
   become_user: www-data
-  when: code_submitter_repo.changed  # noqa: no-handler - Use a handler to ensure execution order
+  when: code_submitter_repo.changed or detect_database.changed  # noqa: no-handler - Use a handler to ensure execution order
 
 - name: Enable service
   service: