Add Troubleshooting guide

This guide described common Resin CLI issues and how to fix them.

README.md

@@ -53,7 +53,7 @@ Caveats
 Support
 -------
 
-If you're having any problem, please [raise an issue](https://github.com/resin-io/resin-cli/issues/new) on GitHub and the Resin.io team will be happy to help.
+If you're having any problem, check our [troubleshooting guide](https://github.com/resin-io/resin-cli/blob/master/TROUBLESHOOTING.md) and if your problem is not addressed there, please [raise an issue](https://github.com/resin-io/resin-cli/issues/new) on GitHub and the Resin.io team will be happy to help.
 
 License
 -------

TROUBLESHOOTING.md

@@ -0,0 +1,15 @@
+Troubleshooting
+===============
+
+This document contains common issues related to the Resin CLI, and how to fix them.
+
+### After burning to an sdcard, my device doesn't boot
+
+- The downloaded image is not complete (download was interrupted).
+
+Please clean the cache (`%HOME/.resin/cache` or `C:\Users\<user>\_resin\cache`) and run the command again. In the future, the CLI will check that the image is not complete and clean the cache for you.
+
+### I get a permission error when burning to an sdcard
+
+- The SDCard is locked.
+- The burning operation is not 100% reliable in Windows 10. We're working on it at the moment.