Resources for helping junior devs learn and grow their skillsets

Cross-posting from Slack:

I have been playing around with an idea to help junior level developers grow their skills. Very much just a prototype at this point (and only one lesson developed so far), but would love your thoughts: https://github.com/conradsp/SeniorDevSchool and https://github.com/conradsp/SeniorDevSchool/tree/master/Lesson1-Docker

@harensen @downey @nribeka