Adds diagram giving overview of CTA authentication

doc/latex/.gitignore

@@ -8,3 +8,4 @@
 *.out
 *.pdf
 *.toc
+*.swp

doc/latex/CTA_Admin_Install.tex

@@ -289,7 +289,14 @@ Create the CTA user:
 \end{lstlisting}
 The CTA Front End requires both Kerberos and SSS authentication: Kerberos is used to authenticate user archive\slash
 retrieve commands and admin commands. SSS is used to authenticate communication between the Front End and CTA/EOS
-\texttt{mgm}.
+\texttt{mgm}. See Figure~\ref{fig:cta_krb5_sss_keys} for an overview.
+
+\begin{figure}[p]
+\centering
+\includegraphics[width=\textwidth]{cta_krb5_sss_keys.png}
+\caption{Authentication Mechanisms in CTA}
+\label{fig:cta_krb5_sss_keys}
+\end{figure}
 
 \subsection{CTA Front End Kerberos Authentication}