database support

Signed-off-by: Alexey Aristov <aav@acm.org>

etc/migrations/V1__initial.sql

@@ -0,0 +1,17 @@
+create table blob(
+    key text not null, 
+    hash text not null
+);
+
+create unique index blob_key on blob(key);
+create unique index blob_hash on blob(hash);
+
+
+create table object(
+    workspace uuid not null,
+    key text not null,
+    part int not null,
+    data jsonb not null,
+
+    primary key (workspace, key, part)
+)