Fix backlinks

Author: gjong

docs/architecture/design/backend-design.adoc

@@ -1,5 +1,5 @@
 :page-nav-title: Backend design
-:page-parent: architecture::backend
+:page-parent: architecture::design
 :page-title: The backend design for Pledger.io
 :page-section: architecture
 :page-layout: section

docs/architecture/design/deployment.adoc

@@ -1,5 +1,5 @@
 :page-nav-title: Deployment
-:page-parent: architecture::deployment
+:page-parent: architecture::design
 :page-title: Deployment strategy for Pledger.io
 :page-section: architecture
 :page-layout: section

docs/architecture/design/repositories.adoc

@@ -1,5 +1,5 @@
 :page-nav-title: Repository setup
-:page-parent: architecture::repositories
+:page-parent: architecture::design
 :page-title: Repositories involved for Pledger.io
 :page-section: architecture
 :page-layout: section

docs/architecture/design/ui-design.adoc

@@ -1,5 +1,5 @@
 :page-nav-title: UI design
-:page-parent: architecture::ui
+:page-parent: architecture::design
 :page-title: The UI design for Pledger.io
 :page-section: architecture
 :page-layout: section