move old docs over

site/content/docs/09-building.md

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+---
+title: Building
+---
+
+Up until now we've been using `sapper dev` to build our application and run a development server. But when it comes to production, we want to create a self-contained optimized build.
+
+### sapper build
+
+This command packages up your application into the `__sapper__/build` directory. (You can change this to a custom directory, as well as controlling various other options — do `sapper build --help` for more information.)
+
+The output is a Node app that you can run from the project root:
+
+```bash
+node __sapper__/build
+```