Fix URLs to the GraphQL Specification and its repository (#514)

Author: IvanGoncharov

README.md

@@ -260,7 +260,7 @@ for example:
 
 ## Additional Validation Rules
 
-GraphQL's [validation phase](https://facebook.github.io/graphql/#sec-Validation) checks the query to ensure that it can be successfully executed against the schema. The `validationRules` option allows for additional rules to be run during this phase. Rules are applied to each node in an AST representing the query using the Visitor pattern.
+GraphQL's [validation phase](https://graphql.github.io/graphql-spec/#sec-Validation) checks the query to ensure that it can be successfully executed against the schema. The `validationRules` option allows for additional rules to be run during this phase. Rules are applied to each node in an AST representing the query using the Visitor pattern.
 
 A validation rule is a function which returns a visitor for one or more node Types. Below is an example of a validation preventing the specific fieldname `metadata` from being queried. For more examples see the [`specifiedRules`](https://github.com/graphql/graphql-js/tree/master/src/validation/rules) in the [graphql-js](https://github.com/graphql/graphql-js) package.
 

src/index.js

@@ -339,7 +339,7 @@ function graphqlHTTP(options: Options): Middleware {
  })
  .then(result => {
  // Collect and apply any metadata extensions if a function was provided.
- // http://facebook.github.io/graphql/#sec-Response-Format
+ // http://graphql.github.io/graphql-spec/#sec-Response-Format
  if (result && extensionsFn) {
  return Promise.resolve(
  extensionsFn({
@@ -368,7 +368,7 @@ function graphqlHTTP(options: Options): Middleware {
  // error, indicate as such with a generic status code.
  // Note: Information about the error itself will still be contained in
  // the resulting JSON payload.
- // http://facebook.github.io/graphql/#sec-Data
+ // http://graphql.github.io/graphql-spec/#sec-Data
  if (response.statusCode === 200 && result && !result.data) {
  response.statusCode = 500;
  }