Update README.md

[deed02392]

Add a note about minimum mongodb version, since Debian 9 stretch has too old a version causing functionality to break without useful error messages

Commit Message Guidelines

Header
Blank Line
Body
Blank Line
Footer

The header should look like:
<type>(<scope>): <subject>

The body should have any necessary detailed info about the commit:
An example, references as to where this idea came from, etc.

The footer should have all the issues tagged:
Fixes #123, Fixes #456

So a commit should look like:
feat(users): Add new Yahoo authentication

Yahoo authentication idea proposed by @codydaig
Example implementation in file.js

Fixes #82

• Types:
  • feat - Features, Enhancements, and overall Improvements
  • fix - Fixes, Bugs, HotFixs, etc...
  • doc - Changes to the Documentation and doesn't actually touch any code.
• Scope:
  • The scope should be where the change took place.
  • Examples: users, core, config, articles
• Subject:
  • The subject line should be clear and concise as to what is being accomplished in the commit.
• General Rules:
  • No Line in the Commit message can be longer than 80 characters.
• Reference: Angular Conventions