change db from sqlite3 to postgresql

assets/migrations/postgresql/20250102232127_article_fts.sql

@@ -0,0 +1,15 @@
+-- +goose Up
+-- +goose StatementBegin
+ALTER TABLE articles 
+ADD COLUMN fts_vector tsvector GENERATED ALWAYS AS (
+    to_tsvector('german', coalesce(title, '') || ' ' || coalesce(content, '') || ' ' || coalesce(author, ''))
+) STORED;
+
+CREATE INDEX articles_fts_idx ON articles USING gin(fts_vector);
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+DROP INDEX IF EXISTS articles_fts_idx;
+ALTER TABLE articles DROP COLUMN IF EXISTS fts_vector;
+-- +goose StatementEnd