[Container-tools] Please read before touching ANY schema files

[Tomas Radej]

Hi, everyone.

Forgive me for being patronising and/or passive aggressive, but please 
*always* read the manual before touching any of the schema files [1]. 
The IETF JSON Schema Internet Draft 4 (which we are using) is a 
well-defined standard for writing JSON schema specification, but it 
doesn't always work as you may expect. For those reasons, please always 
refer to [2] (the standard) or [3] (a nice reference book) before you 
make any changes to the schema files, or *especially* if you're about to 
merge a pull request that does.

I am prompted to write this e-mail after several occurrences of people 
writing or modifying the files without checking the standard first. On a 
couple of occasions already, this meant that my effort went to waste 
because I fixed it only to see it rewritten by someone else in a manner 
incompatible with the standard again.

If you find the documentation daunting or confusing, just contact me, 
I'll be glad to help. I'll be working with the relevant people now on 
fixing what's currently broken in the spec.

Thank you, Tomas

[1] https://github.com/projectatomic/nulecule/tree/master/spec
[2] http://json-schema.org/latest/json-schema-validation.html
[3] 
http://spacetelescope.github.io/understanding-json-schema/reference/index.html