Add production support for SQLite

server/.env.example

@@ -1,6 +1,7 @@
 # Environment configuration for KCA. Copy to .env or export the variables.
 
 # --- Database --------------------------------------------------------------
+# PostgreSQL (default). Run `aerich upgrade` before starting the app.
 DATABASE_ENGINE=postgres
 DATABASE_HOST=localhost
 DATABASE_PORT=5432
@@ -10,6 +11,15 @@ DATABASE_PASSWORD=password
 #DATABASE_OPTIONS=
 #DATABASE_URL=
 
+# SQLite production alternative: DATABASE_NAME is an absolute or relative file
+# path; host, port, user and password are ignored. Use a persistent writable
+# filesystem and run `aerich upgrade` before starting the app.
+#DATABASE_ENGINE=sqlite
+#DATABASE_NAME=/data/kca.db
+#DATABASE_OPTIONS=busy_timeout=5000
+# Equivalent single-setting form:
+#DATABASE_URL=sqlite:///data/kca.db?busy_timeout=5000
+
 # --- OIDC ------------------------------------------------------------------
 # Indexed blocks OIDC_0_*, OIDC_1_*, ... with contiguous indices from 0.
 OIDC_0_PROVIDER=default