Fix PRERELEASE for branch

MSP-9819
Port templates from metasploit-credential

MSP-9819
Improved README

MSP-9818

Fill in description and add .yardopts changes to README.
Fix typo

MSP-9818
Add example ERDs to README

MSP-9818
Add class loading instructions to README

MSP-9818
Fix fork URL rendering

MSP-9818

Markdown was hiding the metavariable because it was surrounded by < >
which weren't quoted in ``, so they were being interpretted as inline
HTML.  Additionally, the URL uses http instead of https.
Index ERD

MSP-9818

Add an ERD for the entire project to _index.html.  This ERD is necessary
for actual Rails application where there is usually not a top-level
namespace module like there would be in Rails::Engines.
Add index page to README

MSP-9819

Add clause mentioning that the index gets a full ERD now.
Merge branch 'master' into feature/port

MSP-9819

Conflicts:
	README.md
Ensure GitHub username is visible in fork link
Merge pull request #2 from rapid7/feature/port

Port templates