addition of new dashboard

backend/db/migrations/000016 - cache.sql

@@ -0,0 +1,14 @@
+-- Per-tenant read-through cache; updated_ts drives TTL freshness.
+CREATE TABLE IF NOT EXISTS public.cache (
+    id          BIGSERIAL PRIMARY KEY,
+    user_id     BIGINT NOT NULL REFERENCES public.user(id),
+    tag         TEXT NOT NULL,
+    data        JSONB NOT NULL,
+    created_ts  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_ts  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    CONSTRAINT uniq__cache__user_id_tag UNIQUE (user_id, tag)
+);
+CREATE INDEX IF NOT EXISTS idx__public__cache__user_id    ON public.cache (user_id);
+CREATE INDEX IF NOT EXISTS idx__public__cache__tag        ON public.cache (tag);
+CREATE INDEX IF NOT EXISTS idx__public__cache__created_ts ON public.cache (created_ts);
+CREATE INDEX IF NOT EXISTS idx__public__cache__updated_ts ON public.cache (updated_ts);