* Documentation for postgresql default port
A port is necessary for postgresql config. Add postgresql default port 5432 in documentation for LNBITS_DATABASE_URL config
* Update docs/guide/installation.md
Co-authored-by: calle <93376500+callebtc@users.noreply.github.com>
Co-authored-by: calle <93376500+callebtc@users.noreply.github.com>