For a small project, it is more economical to run MySQL server in Ubuntu 20.04 than to subscribe Amazon RDS. To install run the commands below.
sudo apt update
sudo apt upgrade -y
sudo apt install -y mysql-server
By default MySQL server bind address is set to 127.0.0.1. Run the command below to edit the configuration file and set it to 0.0.0.0 which binds to all addresses.
sudo vim /etc/mysql/mysql.conf.d/mysqld.cnf