Json schema to provide coding assistance for goss.yaml in IDEs (#793)

* Initial addition of goss json schema

Limitations / missing support
- meta
- title
- patterns
- advanced matchers
- templates

* Document using Json schema draft 7

* Document maintaining Json schema

* Json schema support for matching

* Refine Json schema with initial support for matcher illustrated in examples

Full support requires including full matchers grammar into the json-schema

* Refine Json schema with title and meta attributes

README.md

@@ -172,7 +172,13 @@ curl -H "Accept: application/vnd.goss-rspecish" localhost:8080/healthz
 
 ### Manually editing Goss files
 
-Goss files can be manually edited to use:
+Goss files can be manually edited to improve readability and expresssiveneess of tests.
+
+A [Json draft 7 schema](https://github.com/json-schema-org/json-schema-spec/blob/draft-07/schema.json) available in [docs/goss-json-schema.yaml](./docs/goss-json-schema.yaml) makes it easier to edit simple goss.yaml files in IDEs, providing usual coding assistance such as inline documentation, completion and static analysis.
+
+For example, to configure the Json schema in JetBrains intellij IDEA, follow [documented instructions](https://www.jetbrains.com/help/idea/json.html#ws_json_schema_add_custom), with arguments such as `schema url=https://raw.githubusercontent.com/goss-org/goss/master/docs/goss-json-schema.yaml`, `schema version=Json schema version 7`, `file path pattern=*/goss.yaml`
+
+In addition, Goss files can also be further manually edited (without full json support) to use:
 
 * [Patterns](https://github.com/goss-org/goss/blob/master/docs/manual.md#patterns)
 * [Advanced Matchers](https://github.com/goss-org/goss/blob/master/docs/manual.md#advanced-matchers)