Add repository commands for handling votes

db/migrations/001_create_votes.sql

@@ -0,0 +1,8 @@
+CREATE EXTENSION IF NOT EXISTS pgcrypto;
+
+CREATE TABLE IF NOT EXISTS votes (
+    slug text not null,
+    voter_id uuid not null,
+    created_at timestamptz NOT NULL DEFAULT timezone('utc'::text, now()),
+    primary key (slug, voter_id)
+);