apps: Add date

apps/CMakeLists.txt

@@ -10,3 +10,4 @@ luna_app(init.c init)
 luna_app(cat.c cat)
 luna_app(edit.c edit)
 luna_app(sh.c sh)
+luna_app(date.c date)

apps/date.c

@@ -0,0 +1,10 @@
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+
+int main()
+{
+    time_t now = time(NULL);
+
+    fputs(ctime(&now), stdout);
+}