[ADD] openacademy: Adding business logic. T#57454

[ejdecena]

Exercise 20: Add a duplicate option. Exercise 19: Add SQL constraints. Exercise 18: Add Python constraints. Exercise 17: Warning. Exercise 16: Active objects – Default values. Exercise 15: Computed fields. Exercise 14: More complex domains. Exercise 13: Domains on relational fields. Exercise 12: Alter existing content. Exercise 11: Multiple many2many relations.

[ejdecena]

What should I do to resolve the conflict? @luisg123v

[luisg123v]

@ejdecena remember to rebase before every push:

git checkout 15.0
git pull origin 15.0
git checkout 15.0-exercises-dev-ejdecena
git rebase 15.0
git push -f origin 15.0-exercises-dev-ejdecena

[ejdecena]

Got it, thanks.