schema: add a README

schema/README.md

@@ -0,0 +1,32 @@
+# JSON schema
+
+## Overview
+
+This directory contains the [JSON Schema](http://json-schema.org/) for
+validating the `config.json` of this container runtime specification.
+
+The layout of the files is as follows:
+* [schema.json](schema.json) - the primary entrypoint for the whole schema document
+* [schema-linux.json](schema-linux.json) - this schema is for the Linux-specific sub-structure
+* [defs.json](defs.json) - definitions for general types
+* [defs-linux.json](defs-linux.json) - definitions for Linux-specific types
+* [validate.go](validate.go) - validation utility source code
+
+
+## Utility
+
+There is also included a simple utility for facilitating validation of a
+`config.json`. To build it:
+
+```bash
+export GOPATH=`mktemp -d`
+go get ./...
+go build .
+rm -rf $GOPATH
+```
+
+Then use it like:
+
+```bash
+./schema schema.json <yourpath>/config.json
+```

schema/validate.go

@@ -10,7 +10,7 @@ import (
 
 func main() {
 	if len(os.Args[1:]) != 2 {
-		fmt.Printf("ERROR: usage is: %s <schema.json> <config.json>", os.Args[0])
+		fmt.Printf("ERROR: usage is: %s <schema.json> <config.json>\n", os.Args[0])
 		os.Exit(1)
 	}