[docs] Remove redundant steps for installing for development

[pandafy]

Steps for installing openwisp-users for development are redundant in README.rst.

[nemesifier]

You mean what is written here: https://github.com/openwisp/openwisp-users#install-development-version is repeated afterwards?

The first one can be removed I think.

[pandafy]

Yes @nemesisdesign . (Getting permalink for rendered document is not straight forward as with other code. 😅 )
These specific lines should be removed

openwisp-users/README.rst

Lines 58 to 65 in 1ad5082

	If you want to contribute, install your cloned fork:
	.. code-block:: shell
	git clone git@github.com:<your_fork>/openwisp-users.git
	cd openwisp-users
	python setup.py develop

[nemesifier]

@pandafy you can proceed if you want

[pandafy]

I think this can be a good first issue for new contributors. I don't feel there is an urgency to fix it, let me know if there is. I will create a patch for it if required urgently.

I will suggest to label them as docs and good first issue to make it easier to find.

[codesankalp]

@pandafy
please see this : #118