migrations do not work after cloning from scratch

[bhemmer]

when cloning the repository and running makemigrations, django need input for a lot of default values

[bhemmer]

#02ae996 on branch migrations does the following:

• remove migrations from gitignore (see add migrations to git #255)
• change migrations 0001 and 0002

When cloning from scratch, running makemigrations asked me to specify a lot of defaults. With the new migrations this does not happen.
With the updated migrations, running migrate from scratch and afterwards copying the previous development DB works. This would be helpful for new contributors.

I am not sure how this will impact production though. @spuetz could you please review that?
I have not much experience with migrations: Is doing this a bad idea?
Should we do a PR for this?