application/javascript was set in commit 5e501844a7 which works, but causes browsers to throw lots of errors in the console, as they try to parse those scripts as javascript, json type still works and doesn't have same issue with browsers
Rename 'make build' to 'make docker-image' so it's more obvious what it's doing
Initialize git submodules automatically when needed, so users don't need to do it manually
Go 1.8 introduced checking of script type and templates are no longer loading, as the script type is not allowed by Go 1.8
https://github.com/golang/go/issues/18569 captures the details.
Change template script type to one of the allowed types, it doesn't matter for clientside-haml-js, it only needs to match the script id
