Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/app/current/connectToDatabase.php on line 12

Warning: mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/app/current/connectToDatabase.php on line 12

Fatal error: Uncaught Error: Call to a member function select_db() on bool in /var/app/current/gun-deaths/categorization/index.php:5
Stack trace:
#0 {main}
  thrown in /var/app/current/gun-deaths/categorization/index.php on line 5