docs/README.md: Tweak document template

Let's tweak the docs/README.md (which is used as the user guide)
to fit Duke better. Specifically,

1. mention product name in the title
2. mention adding a product screenshot and a product intro
3. tweak the flow to describe feature-by-feature

docs/README.md

@@ -1,29 +1,30 @@
-# User Guide
+# Duke User Guide
 
-## Features 
+// Update the title above to match the actual product name
 
-### Feature-ABC
+// Product screenshot goes here
 
-Description of the feature.
+// Product intro goes here
 
-### Feature-XYZ
+## Adding deadlines
 
-Description of the feature.
+// Describe the action and its outcome.
 
-## Usage
+// Give examples of usage
 
-### `Keyword` - Describe action
+Example: `keyword (optional arguments)`
 
-Describe the action and its outcome.
+// A description of the expected outcome goes here
 
-Example of usage: 
+```
+expected output
+```
 
-`keyword (optional arguments)`
+## Feature ABC
 
-Expected outcome:
+// Feature details
 
-Description of the outcome.
 
-```
-expected output
-```
+## Feature XYZ
+
+// Feature details