grunt in glossary

js-glossary.md

@@ -15,5 +15,12 @@ Amber itself is a client-side web package, so Amber itself is a bower package an
 
 Amber web project (a client-side web project that uses Amber) is encouraged to use bower to manage its dependencies as well, listing Amber itself as one of them. Default projects (the ones created by `amber init`) do just that.
 
+### What is `grunt`?
+
+Grunt is build system for JS ecosystem. In root directory of the project, grunt looks for `Gruntfile.js` which defines tasks to be done and binds them together, similarly as `Makefile` did for `make` build system for UNIX. Grunt is installed via npm and must be installed in three parts: `grunt` - the runtime, installed as development dependency of the project, `grunt-xxx-yyy` - modules with reusable tasks, also as development dependency of the project, and `grunt-cli`, the CLI command that drives the runtime using `Gruntfile.js`, which should be installed globally.
+
+### Where is `grunt` used in Amber?
+
+Amber itself and default Amber projects (the ones created by `amber init`) both contain `Gruntfile.js` and they include `grunt` and accompanying grunt task modules as development dependencies. In Amber project, grunt is used to recompile Smalltalk source to JavaScript files from CLI, as well as running the tests from CLI. In Amber itself, grunt is used for the same, plus a few bookkeeping tasks.