Move architecture section to the top

doc/install/aws/index.md

@@ -13,12 +13,6 @@ including the database, will be hosted on the same instance.
 If you are interested for a highly available environment, check the
 [high availability docs](../../administration/high_availability/README.md).
 
-## Architecture
-
-Below is the diagram of the architecture.
-
-![AWS architecture](img/aws_diagram.png)
-
 ## Requirements
 
 A basic familiarity with AWS and EC2 is assumed. In particular, you will need:
@@ -28,6 +22,12 @@ A basic familiarity with AWS and EC2 is assumed. In particular, you will need:
   an SSH key to connect to the instance via SSH
 - A domain name under which GitLab will be reached
 
+## Architecture
+
+Below is the diagram of the architecture.
+
+![AWS architecture](img/aws_diagram.png)
+
 ## Costs
 
 Based on [GitLab's requirements](../requirements.md#hardware-requirements), the