Add readme

README.md

@@ -1,3 +1,46 @@
-# Countries
+# Countries GraphQL API
 
-[![Build Status](https://travis-ci.com/trevorblades/countries.svg?branch=master)](https://travis-ci.com/trevorblades/countries)
+[![Build Status](https://travis-ci.com/trevorblades/countries.svg?branch=master)](https://travis-ci.com/trevorblades/countries)
+
+A public GraphQL API for data about countries, continents, and languages. This project uses [Countries list](https://annexare.github.io/Countries/) as a data source, so the schema follows the shape of that data, with a couple exceptions:
+
+1. The codes used to key the objects in the original data are available as a `code` property on each item returned from the API.
+2. The `continent` and `languages` properties are now objects and arrays of objects, respectively.
+
+Check out the [playground](https://countries.trevorblades.com) to explore the schema and test out some queries.
+
+## Example
+
+```graphql
+{
+  country(code: "BR") {
+    name
+    native
+    emoji
+    currency
+    languages {
+      code
+      name
+    }
+  }
+}
+```
+
+```json
+{
+  "data": {
+    "country": {
+      "name": "Brazil",
+      "native": "Brasil",
+      "emoji": "🇧🇷",
+      "currency": "BRL",
+      "languages": [
+        {
+          "code": "pt",
+          "name": "Portuguese"
+        }
+      ]
+    }
+  }
+}
+```