VCIO-next: Create improver to find fix commits

[pombredanne]

We should collect fix commits from existing references using a new improver.

This improver pipeline that will scout the References to create CodeFix entries.

This will be using the CodeFix models designed in:

• VCIO-next: Add support to track fix commits: Include commits and patches that fix a vulnerability #207 (comment)

And is in support of the larger fix commit collection issue at:

• Collect all fix commits #1703

See also these related issues:

• Infer Package URL from references and other references issues for "commitish" URLs  #327

[TG1999]

This is done now.

We have completed this issue in #1704. To test this setup Vulnerablecode locally with the help of Readme. After setting up VCIO. Run any importer for example ./manage.py import npm_importer. Then run ./manage.py improve collect_fix_commits. Then run the server using make run and go to /api/v2/packages. You can find list of "code_fixes" for for a package in "affected_by_vulnerabilities" like the screenshots below.