restructured, added db connection pool

migrations/20240214155303_create_subscriptions_table.sql

@@ -0,0 +1,8 @@
+-- Add migration script here
+CREATE TABLE subscriptions(
+  id uuid NOT NULL,
+  PRIMARY KEY (id),
+  email TEXT NOT NULL UNIQUE,
+  name TEXT NOT NULL,
+  subscribed_at timestamptz NOT NULL
+);