[threeseed]

Or use Dex: https://github.com/dexidp/dex

Which has the advantage of not needing any external databases.

[snuxoll]

That works too depending on your requirements. Either way, authentication is not a hard problem to solve.

[kissgyorgy]

LOL. You clearly not worked with SSO or anything a bit more complex. It's a pretty hard problem, there are even companies whose whole portfolio is around authentication only!