Add db migration to update some votes results (#658)

Signed-off-by: Sergio Castaño Arteaga <tegioz@icloud.com>

Author: tegioz

database/migrations/schema/004_update_results.sql

@@ -0,0 +1,13 @@
+update vote set
+    results = jsonb_set(results, '{against_percentage}', to_jsonb((results->>'against')::real / (results->>'allowed_voters')::real * 100))
+where results is not null
+and results != 'null'::jsonb
+and not results ? 'against_percentage';
+
+update vote set
+    results = jsonb_set(results, '{pending_voters}', '[]'::jsonb)
+where results is not null
+and results != 'null'::jsonb
+and not results ? 'pending_voters';
+
+---- create above / drop below ----