format boxes

presentation/presentation.md

@@ -59,10 +59,14 @@ func main() {
 ---
 # Boxes
 
+<center>
+
 <box>Build environment</box> $\rightarrow$
 <box>Compile</box> $\rightarrow$
 <box>Deploy</box>
 
+</center>
+
 ---
 # Done!
 - Thanks for your attention!