Give a plugin a Postgres database of its own

ory/postgres/init/init.sql

@@ -1,6 +1,7 @@
 -- Runs once on first boot (docker-entrypoint-initdb.d), as the POSTGRES_USER.
 -- One database per Ory service: each owns its schema and runs its own migrations,
--- so they never collide. The web app never connects here (stateless — see README).
+-- so they never collide. A plugin's database does not belong here: bootstrap provisions those on
+-- every boot, so one dropped in later is picked up too (README → Plugin storage).
 CREATE DATABASE kratos;
 CREATE DATABASE keto;
 CREATE DATABASE hydra;