Like so:

    function save_database() {
        mkdir -p /tmp/database-snapshots
        DATABASE_NAME=$PROJECT_NAME
        pg_dump -Fc "$DATABASE_NAME" >"/tmp/database-snapshots/$DATABASE_NAME.dump"
    }

    function restore_database() {
        DATABASE_NAME=$PROJECT_NAME
        DATABASE_DUMP="/tmp/database-snapshots/$DATABASE_NAME.dump"

        if [ ! -f "$DATABASE_DUMP" ]; then
            echo "No dump to restore"
            return
        else
            psql postgres -c 'SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE pid <> pg_backend_pid()'
            psql postgres -c "DROP DATABASE IF EXISTS \"$DATABASE_NAME\""
            psql postgres -c "CREATE DATABASE \"$DATABASE_NAME\""
            pg_restore -Fc -j 8 -d "$DATABASE_NAME" "$DATABASE_DUMP"
        fi
    }