Add documentation and modify template to include git-secret encrypted data

[oindrillac]

Is your feature request related to a problem? Please describe.
Some of our projects rely on sensitive data for which we use private git repos and we wish to store the data encrypted within the git repo. For the purposes of encryption, we are using git-secret. The project template currently does not have provisions for uploading encrypted data to the Github Repository.

Describe the solution you'd like

• Include a doc into the template, or possibly update the readme, to include a section on how to encrypt and decrypt data while working on these projects.
• Modify "cookie-cutter" project template, specifically data directory and .gitignore to include secret files.

Describe alternatives you've considered
Other alternatives have not been considered for encryption and storage within Git repos, but open to suggestions.