Merge pull request #21 from adidas/ruleset

Add ruleset extracted from the guidelines

ruleset.md

@@ -0,0 +1,23 @@
+# Adidas API Guidelines Ruleset
+
+- all JSON fields MUST follow `camelCase`
+- field names MUST be ASCII alphanumeric characters or `_` or `$`
+- collection/array fields MUST have names in plural
+- all requests go through `https` protocol
+- every API operation MUST have at least one `2xx` response
+- `GET` request MUST NOT accept a `body` parameter
+- all success responses MUST be of media type `application/hal+json`
+- all error responses MUST be of media type `application/problem+json`
+- every request SHOULD support `application/json` media type
+- `application/hal+json` follows https://supermodel.io/adidas/api/HAL `JSON-Schema`
+- `application/problem+json` messages MUST include `title` and `detail` fields
+- `application/problem+json` messages SHOULD include `type` field
+- date and time MUST follow `ISO 8601` standard: https://www.iso.org/iso-8601-date-and-time-format.html
+- language codes MUST follow `ISO 639` standard: https://www.iso.org/iso-639-language-codes.html
+- country codes MUST follow `ISO 3166 alpha-2` standard: https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2
+- currency codes MUST follow `ISO 4217` standard: https://en.wikipedia.org/wiki/ISO_4217
+- `202` response code is used after creating an asynchronous process request
+- a successful and finished async api request returns `303` response code and sends the target resource location in the `Link` header
+- `URI` template ([RFC 6570](https://tools.ietf.org/html/rfc6570)) cannot contain a `-` character
+- `HTTP` headers MUST use `Hyphenated-Pascal-Case` notation
+- `HTTP` headers SHOULD NOT include `X-` headers (https://tools.ietf.org/html/rfc6648). All non-standard headers are named without the `X-` prefix.