Add Static Analysis for webapp documentation

Author: Julien Neuhart

docs/docs/4_Web Application/4_3_Static Analysis.md

@@ -0,0 +1,38 @@
+---
+title: Static Analysis
+slug: /webapp/static-analysis
+---
+
+The boilerplate provides static analysis tools for helping you catch common mistakes and format your source code.
+
+:::note
+
+📣  All commands have to be run in the `webapp` service (`make webapp`).
+
+:::
+
+## ESLint
+
+[ESLint](https://eslint.org/) is both a linting and a formatting tool.
+
+It also comes with [Prettier](https://prettier.io/) that provides more rules.
+
+It will parse your JavaScript and CSS source code, catch common mistakes plus format it.
+
+This command will try to fix and format your source code:
+
+```bash title="console"
+yarn lint:fix
+```
+
+This command will verify your source code:
+
+```bash title="console"
+yarn lint
+```
+
+:::note
+
+📣  In your development environment, hot reloading automatically runs the lint command.
+
+:::