A video about ActiveRecord Association is missing

Hi
firstable i want to thank you about this rich content website , you push me to the more advanced rails dev
I have suggestion why not doing a video explain the ActiveRecord Association and it's API for example for the relation has_many

collection
collection<<(object, ...)
collection.delete(object, ...)
collection.destroy(object, ...)
collection=(objects)
collection_singular_ids
collection_singular_ids=(ids)
collection.clear
collection.empty?
collection.size
collection.find(...)
collection.where(...)
collection.exists?(...)
collection.build(attributes = {}, ...)
collection.create(attributes = {})
collection.create!(attributes = {})
collection.reload

really I check the whole youtube i didnot found such video .

and thank you a lot

Great idea!