Add missing comma. (graphql#412)

davidgomes · Sashko Stubailo · commit 400e87036197 · 2017-11-26T16:00:38.000-08:00
diff --git a/site/learn/Learn-Execution.md b/site/learn/Learn-Execution.md
@@ -87,7 +87,7 @@ human(obj, args, context) {
 }
 ```
 
-The `context` is used to provide access to a database which is used to load the data for a user by the `id` provided as an argument in the GraphQL query. Since loading from a database is an asynchronous operation, this returns a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise). In JavaScript Promises are used to work with asynchronous values, but the same concept exists in many languages, often called *Futures*, *Tasks* or *Deferred*. When the database returns, we can construct and return a new `Human` object.
+The `context` is used to provide access to a database which is used to load the data for a user by the `id` provided as an argument in the GraphQL query. Since loading from a database is an asynchronous operation, this returns a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise). In JavaScript, Promises are used to work with asynchronous values, but the same concept exists in many languages, often called *Futures*, *Tasks* or *Deferred*. When the database returns, we can construct and return a new `Human` object.
 
 Notice that while the resolver function needs to be aware of Promises, the GraphQL query does not. It simply expects the `human` field to return something which it can then ask the `name` of. During execution, GraphQL will wait for Promises, Futures, and Tasks to complete before continuing and will do so with optimal concurrency.
 

Original file line number	Diff line number	Diff line change
`@@ -87,7 +87,7 @@ human(obj, args, context) {`
`87`	`87`	`}`
`88`	`88`	```
`89`	`89`
`90`		-The `context` is used to provide access to a database which is used to load the data for a user by the `id` provided as an argument in the GraphQL query. Since loading from a database is an asynchronous operation, this returns a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise). In JavaScript Promises are used to work with asynchronous values, but the same concept exists in many languages, often called Futures, Tasks or Deferred. When the database returns, we can construct and return a new `Human` object.
	`90`	+The `context` is used to provide access to a database which is used to load the data for a user by the `id` provided as an argument in the GraphQL query. Since loading from a database is an asynchronous operation, this returns a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise). In JavaScript, Promises are used to work with asynchronous values, but the same concept exists in many languages, often called Futures, Tasks or Deferred. When the database returns, we can construct and return a new `Human` object.
`91`	`91`
`92`	`92`	Notice that while the resolver function needs to be aware of Promises, the GraphQL query does not. It simply expects the `human` field to return something which it can then ask the `name` of. During execution, GraphQL will wait for Promises, Futures, and Tasks to complete before continuing and will do so with optimal concurrency.
`93`	`93`