Django - makemigrations - No changes detected
One more edge case and solution: 
I added a boolean field, and at the same time added an @property referencing it, with the same name (doh). Commented the property and migration sees and adds the new field. Renamed the property and all is good.
I was trying to create migrations within an existing app using the makemigrations command but it outputs "No changes detected".
Usually I create new apps using the startapp command but did not use it for this app when I created it.
After debugging, I found that it is not creating migration because the migrations package/folder is missing from an app. 
Would it be better if it creates the folder if it is not there or am I missing something?