Codecademy "Learn Ruby on Rails" notes

But the majority of the course is of the "type this and look at the results" without much explanation of what I just typed and why. Example: After writing a few lines of Ruby code, the student is instructed to go into the command prompt and type "rake db:migrate" followed by "rake db:seed" before instructed to marvel at the result of the magic.
What did that do? The class didn't really say beyond "made database". Afterwards I went back and dig into the documentation to come up with a guess at what's going on:
The lines of code turned out to be a way to define schema for a database table. After the schema is updated, the table itself is migrated from the previous schema to the new schema. In this case there is no existing table, so 'migrate' creates a new empty one. Then "db:seed" inserts some information pre-generated by the Codecademy course author into the just-created database so it is not empty.
And "rake", which I had inferred to be some kind of database tool, is actually a general task running tool like "make" for C. I got the wrong impression since all I saw were database tasks.
That's one example, there were many others. With this lack of explanation I'm sure I have quite a few misconceived notions on how Rails apps are built. Heck, what I described above with 'db:migrate' etc. might be wrong! I'll learn my errors in due course.
If it was titled "Interactive demo of Ruby on Rails" I would be satisfied with what I got, but I don't think it deserves the title "Learn Ruby on Rails" when actual learning has been left as an exercise for the student.