Modify gunicorn service unit file to include environment variables after reboot

Author: samuelselasi

0x1A-application_server/gunicorn.service

@@ -7,6 +7,12 @@ After=syslog.target
 User=ubuntu
 Group=www-data
 WorkingDirectory=/home/ubuntu/AirBnB_clone_v4
+Environment="HBNB_MYSQL_USER=hbnb_dev"
+Environment="HBNB_MYSQL_PWD=hbnb_dev_pwd"
+Environment="HBNB_MYSQL_HOST=localhost"
+Environment="HBNB_MYSQL_DB=hbnb_dev_db"
+Environment="HBNB_TYPE_STORAGE=db"
+ExecStartPre=/usr/bin/tmux new-session -d 'gunicorn --bind 0.0.0.0:5002 api.v1.app:app'
 ExecStart=/home/ubuntu/.local/bin/gunicorn --workers 3 --bind 0.0.0.0:5003 web_dynamic.2-hbnb:app --access-logfile /tmp/airbnb-access.log --error-logfile /tmp/airbnb-error.log
 Restart=on-failure