Permanent swap file tutorial proposed

doc/articles/troubleshooting.md

@@ -283,6 +283,7 @@ To enable the swap you can use for example:
 /sbin/mkswap /var/swap.1
 /sbin/swapon /var/swap.1
 ```
+You can make a permanent swap file following this [tutorial](https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04).
 
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