Start adding tests

Signed-off-by: Nikolai Rodionov <allanger@badhouseplants.net>

internal/helpers/postgres/postgres.go

@@ -0,0 +1,21 @@
+package postgres
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	_ "github.com/jackc/pgx/v5/stdlib"
+)
+
+func Open(ctx context.Context, dsn string) (*pgxpool.Pool, error) {
+	dbpool, err := pgxpool.New(context.Background(), dsn)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := dbpool.Ping(ctx); err != nil {
+		return nil, err
+	}
+
+	return dbpool, nil
+}