\documentclass{article}
\usepackage{pdfpages}

%\VignetteIndexEntry{rrapply: cheat sheet}
%\VignetteAuthor{Joris Chau}
%\VignetteKeyword{introduction}
%\VignetteKeyword{cheatsheet}
%\VignetteKeyword{rrapply}
%\VignetteEncoding{UTF-8}

\begin{document}
\includepdf[pages=-, fitpaper=true]{cheatsheet.pdf}
\end{document}