Add stub page for build system

src/development/build-system.md

@@ -0,0 +1,40 @@
+---
+title: Build system
+show_in_menu: contents
+nav_sort: 40
+---
+
+# Build System
+
+The build process is needed to download third-party libraries, compile
+templates, minify and concatenate JavaScript files, etc. It means that you have
+to use build system if you want to modify Mibew's Core or use the latest
+unreleased version from the respository.
+
+Mibew uses [Gulp.js](http://gulpjs.com/) as a build system. You also needs
+[node.js](https://nodejs.org/) and [npm](https://www.npmjs.com/) to make Gulp
+works. For the most common tasks [PHP](http://php.net/) is also needed.
+
+There are several actions one should do before use the version from the repository:
+
+1. Obtain a copy of the repository using `git clone`, download button, or another way.
+2. Install [node.js](http://nodejs.org/) and [npm](https://www.npmjs.org/).
+3. Install [Gulp](http://gulpjs.com/).
+4. Navigate to `src/` directory of the local copy of the repository.
+5. Install npm dependencies using `npm install`.
+6. Run Gulp to build Mibew using `gulp default`.
+
+Finally `.tar.gz` and `.zip` archives of the ready-to-use Mibew will be
+available in `src/release/` directory.
+
+The `default` task that was used above is just one of many available build
+tasks. The full list can be got by running `gulp -T` in `src/` directory of
+Mibew repository. Here is descripion of the most frequently used tasks:
+
+* `gulp rebuild`: installs all necessary dependencies and compile (minifies, concats,
+  ...) all files that should be compiled. The result of the task is a
+  redy-to-use development version of Mibew.
+* `gulp default`: the same as `gulp rebuild` but also packs the sources into
+  archives under `src/release/` directory.
+* `gulp phpcs`: runs [PHP Code Sniffer](https://github.com/squizlabs/PHP_CodeSniffer)
+  to check if the sources follows coding style.