Added a new sync that uses hash

Added a new sync that uses hash and sqlc for the queries. Added db
migration. Started adding a config file.

db/migrations/000002_adjust_fields_for_sqlc.up.sql

@@ -0,0 +1,19 @@
+BEGIN;
+UPDATE game
+SET number_of_songs = 0
+WHERE number_of_songs IS NULL;
+UPDATE game
+SET hash = ''
+WHERE hash IS NULL;
+UPDATE song
+SET hash = ''
+WHERE hash IS NULL;
+COMMIT;
+BEGIN;
+Alter table game
+alter column number_of_songs set not null,
+alter column number_of_songs set default 0,
+ALTER COLUMN hash SET NOT NULL;
+ALTER TABLE song
+ALTER COLUMN hash SET NOT NULL;
+COMMIT;