Merge pull request #173 from donofriov/feature/update-controller-docs-with-query-params

Add Query Params to Controller Guide (#163)

Author: Jen Weber

guides/v3.4.0/controllers/index.md

@@ -6,6 +6,8 @@ The model is passed from the Route to the Controller by default using the [`setu
 
 A Controller is usually paired with an individual Route of the same name.
 
+[Routing Query Parameters](https://guides.emberjs.com/release/routing/query-params/) should be defined within a controller.
+
 ### Defining a Controller
 
 We only need to generate a Controller file if we want to customize the properties or provide any actions to the Route. If we have no customizations, Ember will provide a default Controller instance for us at run time.
@@ -95,11 +97,11 @@ We can see that if the property `isExpanded` is toggled to true, we will show th
 ### Common questions
 
 ###### Should we use controllers in my application? I've heard they're going away!
-  
+
 Yes! Controllers are still an integral part of an Ember application architecture, and generated by the framework even if you don't declare a Controller module explicitly.
 
 ###### When should we create a Controller?
 
 * We want to pass down actions or variables to share with a Route’s child components
 * We have a computed property that depends on the results of the model hook
-* We need to support query parameters
+* We need to support query parameters