[web] Clarified Singularity usage guides for user and developer.

web/content/docs/devguide/advanced/singularity.md

@@ -9,6 +9,14 @@ weight = 1036
     parent = "advanced"
 +++
 
+<div class='note'>
+
+### Important note
+
+This page describes how to **build** OGS with the help of a Linux container (for **developers**). To **run** OGS with the help of a container go to the [user guide]({{< ref "container.md" >}}) (for **developers**).
+
+</div>
+
 ## Introduction
 
 [Singularity](https://www.sylabs.io) is a Linux container runtime similar to Docker. Key advantages over Docker are

web/content/docs/userguide/basics/container.md

 +++
-date = "2018-11-14T15:00:13+01`:00"
+date = "2018-11-14T15:00:13+01:00"
 title = "Running OGS in a container"
 author = "Lars Bilke"
 weight = 10
@@ -9,6 +9,14 @@ weight = 10
     parent = "basics"
 +++
 
+<div class='note'>
+
+### Important note
+
+This page describes how to **run** OGS with the help of a Linux container (for **users**). To **build** OGS with the help of a container go to the [developer guide]({{< ref "singularity.md" >}}) (for **developers**).
+
+</div>
+
 ## With Singularity
 
 ### Prerequisites