Docs on using fpdf2 with gunicorn

CHANGELOG.md

@@ -23,6 +23,7 @@ This can also be enabled programmatically with `warnings.simplefilter('default',
 * [`Templates`](https://py-pdf.github.io/fpdf2/fpdf/Templates.html) can now be also defined in JSON files.
 * support to optionally set `wrapmode` in templates (default `"WORD"` can optionally be set to `"CHAR"` to support wrapping on characters for scripts like Chinese or Japanese) - _cf._ [#1159](https://github.com/py-pdf/fpdf2/issues/1159) - thanks to @carlhiggs
 * support for quadratic and cubic Bézier curves with [`FPDF.bezier()`](https://py-pdf.github.io/fpdf2/fpdf/Shapes.html#fpdf.fpdf.FPDF.bezier) - thanks to @awmc000
+- documentation on how to use `fpdf2` with [gunicorn](https://gunicorn.org/): [link to docs](https://py-pdf.github.io/fpdf2/UsageInWebAPI.html#gunicorn)
 * feature to identify the Unicode script of the input text and break it into fragments when different scripts are used, improving [text shaping](https://py-pdf.github.io/fpdf2/TextShaping.html) results
 * [`FPDF.image()`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.image): now handles `keep_aspect_ratio` in combination with an enum value provided to `x`
 * [`FPDF.write_html()`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.write_html): now supports CSS page breaks properties : [documentation](https://py-pdf.github.io/fpdf2/HTML.html#page-breaks)

docs/UsageInWebAPI.md

@@ -49,6 +49,28 @@ def hello_world():
 ```
 
 
+## gunicorn ##
+[Gunicorn 'Green Unicorn'](https://gunicorn.org/) is a Python WSGI HTTP Server for UNIX.
+
+The following code can be placed in a `gunicorn_fpdf2.py` file and launched using `gunicorn -w 4 gunicorn_fpdf2:app`:
+
+```python
+from fpdf import FPDF
+
+def app(environ, start_response):
+    pdf = FPDF()
+    pdf.add_page()
+    pdf.set_font("Helvetica", size=12)
+    pdf.cell(text="Hello world!")
+    data = bytes(pdf.output())
+    start_response("200 OK", [
+        ("Content-Type", "application/pdf"),
+        ("Content-Length", str(len(data)))
+    ])
+    return iter([data])
+```
+
+
 ## AWS lambda ##
 The following code demonstrates some minimal [AWS lambda handler function](https://docs.aws.amazon.com/lambda/latest/dg/python-handler.html)
 that returns a PDF file as binary output: