At Wagtail Space US 2018 @patphongs provided some helpful feedback about how to improve the getting started documentation for this package.
This commit adds instructions for getting started with a new sharing site for a local Django development server.
(Note that the new embedded image in the README won't render properly in this PR as it refers to the path at which it would reside once merged; I did this so that the image will show up [on PyPI](https://pypi.org/project/wagtail-sharing/) if/when this gets merged.)
Add a middleware to make wagtail's pageurl templatetag create relative
links. Without this middleware, hyperlinks on sharing.mysite.com will
take a user to mysite.com.
Our reviewers want to review multiple draft pages at once, so the page links should keep a user on the sharing domain.
Added a middleware which will enable page links to keep the sharing domain
Middleware unit tests
[Preview this PR without the whitespace changes](?w=0)
* [ ] Changes are limited to a single goal (no scope creep)
* [ ] Code can be automatically merged (no conflicts)
* [ ] Code follows the standards laid out in the [front end playbook](https://github.com/cfpb/front-end)
* [ ] Passes all existing automated tests
* [ ] New functions include new tests
* [ ] New functions are documented (with a description, list of inputs, and expected output)
* [ ] Placeholder code is flagged
* [ ] Visually tested in supported browsers and devices
* [ ] Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
## Current behavior
The "Draft" status indicator links to nothing
## Desired behavior
The "Draft" status indicator would link to a page's sharing URL, so that people on an editing screen could click directly to the shared page, instead of having to go up a level to access that page's "More" menu to use the "View sharing link" option.