fix typo

thesis/content/05-proof-of-concept/building-block-view.tex

@@ -6,7 +6,7 @@ Figure \ref{fig:building-block-view} shows a black box view of which other syste
 
 \begin{itemize}
 	\item Twitter \ac{API}
-	\item Gun
+	\item GUN
 	\item \ac{IPFS} via Infura
 	\item User 
 \end{itemize}