'Shift Left Security', what the funk does that mean?!

In the agile, lean, devops communities people talk about improving security by “shifting left”.
Patterns and tools are emerging, or re-emerging, that make security less of a pain in the development process while also making applications more secure.
I will cover tools and processes that help teams with the day to day work like code scanners, application scanners, pull requests, deployment tooling and infrastructure-as-code.
At the organisational level some relatively small changes to, for instance, the change approval process can have a big impact.
These are tools and processes that have proven themselves at many organisations and perhaps they can do the same for you.