Since GitHub doesn’t apply these constraints to theirs wiki slug
allowing characters like `,`, `:`, `*`, etc, we need to relax our
constraints or some wiki pages will not be available after they were
imported.
For an example the Devise project have a wiki page with the following
slug: “How To: Add sign_in, sign_out, and sign_up links to your layout
template”
This commit replaces the old database backed Wiki system with the
excellent Gollum git based Wiki system.
The UI has been updated to allow for utilizing the extra features
that Gollum provides. Specifically:
* Edit page now allows you to choose the content format.
* Edit page allows you to provide a commit message for the change.
* History page now shows Format, Commit Message, and Commit Hash.
* A new Git Access page has been added with the Wiki Repo URL.
* The default page has been changed to Home from Index to match
the Gollum standard.
The old Wiki model has been left in tact to provide for the
development of a migration script that will move all content stored
in the old Wiki system into new Gollum Wikis.
