add dogstatsd_tags example to docs

[jasonwbarnett]

When I used this for the first time I wasn't 100% sure how the tags should be specified. If the docs had a small example like this it would have helped.

[pajod]

Thanks.

Not yet ready to merge: You were editing the generated reST file docs/source/settings.rst.

gunicorn/docs/source/settings.rst

Line 1 in 903792f

.. Please update gunicorn/config.py instead.

The documentation for configuration options is stored in the doc-strings of the gunicorn/config.py file and copied to the reST file by sphinx (run make -C docs html).

[jasonwbarnett]

@pajod updated! Thanks for the quick help.