add brief api reference docs for express-graphql

Author: lacker

site/code/index.html.js

@@ -30,7 +30,7 @@ Many different programming languages support GraphQL. This list contains some of
 ## GraphQL Server Libraries
 
   - [GraphQL.js](/graphql-js/getting-started/) ([github](https://github.com/graphql/graphql-js/)) ([npm](https://www.npmjs.com/package/graphql)): The reference implementation of the GraphQL specification, designed for running a GraphQL server in a Node.js environment.
-  - [express-graphql](/graphql-js/getting-started/) ([github](https://github.com/graphql/express-graphql)) ([npm](https://www.npmjs.com/package/express-graphql)): The reference implementation of a GraphQL API server over an Express webserver. You can use this to run GraphQL in conjunction with a regular Express webserver, or as a standalone GraphQL server.
+  - [express-graphql](/graphql-js/running-an-express-graphql-server/) ([github](https://github.com/graphql/express-graphql)) ([npm](https://www.npmjs.com/package/express-graphql)): The reference implementation of a GraphQL API server over an Express webserver. You can use this to run GraphQL in conjunction with a regular Express webserver, or as a standalone GraphQL server.
   - [Graphene](http://graphene-python.org/) ([github](https://github.com/graphql-python/graphene)): A Python library for building GraphQL APIs. Built-in support for [Relay](https://facebook.github.io/relay/), Django, SQLAlchemy, and Google App Engine.
   - [graphql-ruby](https://github.com/rmosolgo/graphql-ruby): A Ruby library for building GraphQL APIs. Built-in support for Relay and Rails.
   - [graphql-java](https://github.com/graphql-java/graphql-java): A Java library for building GraphQL APIs.

site/docs/APIReference-ExpressGraphQL.md

@@ -0,0 +1,35 @@
+---
+title: express-graphql
+layout: ../_core/CodeLayout
+category: API Reference
+permalink: /docs/api-reference-express-graphql/
+sublinks: graphqlHTTP
+next: /docs/api-reference-graphql/
+---
+
+The `express-graphql` module provides a simple way to create an [Express](https://expressjs.com/) server that runs a GraphQL API.
+
+```js
+import graphqlHTTP from 'express-graphql'; // ES6
+var graphqlHTTP = require('graphql'); // CommonJS
+```
+
+### graphqlHTTP
+
+```js
+graphqlHTTP({
+  schema: GraphQLSchema,
+  graphiql?: ?boolean,
+  rootValue?: ?any,
+  context?: ?any,
+  pretty?: ?boolean,
+  formatError?: ?Function,
+  validationRules?: ?Array<any>,
+}): Middleware
+```
+
+Constructs an Express application based on a GraphQL schema.
+
+See the [express-graphql tutorial](/graphql-js/running-an-express-graphql-server/) for sample usage.
+
+See the [GitHub README](https://github.com/graphql/express-graphql) for more extensive documentation of the details of this method.

site/docs/Guides-ConstructingTypes.md

@@ -3,7 +3,7 @@ title: Constructing Types
 layout: ../_core/CodeLayout
 category: Advanced Guides
 permalink: /graphql-js/constructing-types/
-next: /docs/api-reference-graphql/
+next: /docs/api-reference-express-graphql/
 ---
 
 For many apps, you can define a fixed schema when the application starts, and define it using GraphQL schema language. In some cases, it's useful to construct a schema programmatically. You can do this using the `GraphQLSchema` constructor.