Make migrations (mostly) idempotent.

config/sql/annotations.sql

@@ -2,11 +2,11 @@
 
 -- DROP TABLE public.annotations;
 
-CREATE TABLE public.annotations
+CREATE TABLE IF NOT EXISTS public.annotations
 (
   id text NOT NULL,
   annotations xml,
   CONSTRAINT annotations_id_key UNIQUE (id)
 );
 
-GRANT ALL ON TABLE public.annotations TO kemal;
+GRANT ALL ON TABLE public.annotations TO current_user;