added readme

Author: matryer

README.md

@@ -1,2 +1,25 @@
 # graphql
-Low-level GraphQL client for Go
+
+Low-level GraphQL client for Go.
+
+* Simple, familiar API
+* Build and execute any kind of GraphQL request
+
+```go
+ctx := context.Background()
+ctx = graphql.NewContext(ctx, "https://machinebox.io/graphql")
+r := graphql.NewRequest(`
+    query ($key: String!) {
+        items (id:$key) {
+            field1
+            field2
+            field3
+        }
+    }
+`)
+r.Var("key", "value")
+var res ResponseStruct
+if err := r.Run(ctx, &resp); err != nil {
+    log.Fatalln(err)
+}
+```