I'm wanting to make a vertical calendar with tasks listed on certain days. For instance, how can I make the code below list a task on February 19th?
\documentclass{article}
\usepackage[top=15mm, bottom=15mm, left=15mm, right=15mm]{geometry}
\usepackage{tikz}
\usetikzlibrary{calendar}
\begin{document}
\begin{tikzpicture}
\calendar [dates=2016-02-01 to 2016-02-29, day list downward, month label left]
if (weekend) [black!25]
;
\end{tikzpicture}
\end{document}