Fix plural spelling in Category model
Add views & likes attrs to Category, customizing admin's panel
Modify rango's views.index & template, now we have top5 by like categoies on main page
Add categories template and mapping (whole 6 chapter).
Add forms for Category & Page models
Add add_category view
Add add_category.html template & mapping to add_category view in /rango/urls.py
Add clean method to PageForm class
Add proposition to add category if it doesn't exist but have been requested
Add "add page" feature (7.3 Exercises)
Add requirements.txt