add: weekly schedule support

helpers/get_day_of_week.cc

@@ -0,0 +1,12 @@
+#include <netdb.h>
+#include <helpers.h>
+
+int
+helpers::get_day_of_week()
+{
+    time_t t = time(NULL);
+    struct tm *now = localtime(&t);
+    int wday_sun_sat = now->tm_wday;
+    int wday_mon_sun = (wday_sun_sat + 6) % 7;
+    return wday_mon_sun;
+}