We should install elm to successfully build atc
The build fails due to missing an elm binary without `npm install`ing it:
```
$ make -B
cd elm && elm make --warn --output ../public/elm.js --yes src/Main.elm
/bin/sh: elm: command not found
make: *** [public/elm.js] Error 127
```
@@ -26,7 +26,7 @@ brew install go node postgres
Finally use Node to install the javascript tools:
```
-npm install -g uglify-js less less-plugin-clean-css
+npm install -g elm uglify-js less less-plugin-clean-css
```
## Setting up the database
