use env vars for db connection

.gitignore

@@ -1,3 +1,4 @@
 *.swp
 crow.h
 a.out
+testapp

mysql.cpp

@@ -14,7 +14,7 @@ int main(void){
 	sql::ResultSet *res;
 
 	driver = get_driver_instance();
-	con = driver->connect("tcp://ipaddress:3306","usr","pwd");
+	con = driver->connect(std::getenv("DBURL"),std::getenv("DBUSER"),std::getenv("DBPWD"));
 	con->setSchema("timer_backend");
 	stmt = con->createStatement();
 	res = stmt->executeQuery("SELECT seconds FROM sessions;");