Add forking section

sections/forking.tex

@@ -0,0 +1,8 @@
+\section{Rule number 5: forking}
+\begin{frame}{By popular demand}
+    Even though there is no RFC for how to fork a thread whose topic pivoted, we usually do so by changing the subject and appending the old subject in parentheses.
+
+    \begin{center}
+        \texttt{\$new\_subject (was: \$old\_subject)}
+    \end{center}
+\end{frame}

slides.tex

@@ -25,6 +25,7 @@
     \input{sections/plain-text}
     \input{sections/top-posting}
     \input{sections/line-wrap}
+    \input{sections/forking}
 
     \nocite{*}
     \bibliography{refs}