add list-colours command.

DeathSocketCLI/Commands.fs

@@ -6,7 +6,7 @@
         open Validation
         open System.IO
 
-        let showEndOfCommandMessage = "[INFO.] Execution completed."
+        let showEndOfCommandMessage = "[INFO.] Task completed."
 
         let test () = "Death Socket is working."
 
@@ -20,4 +20,10 @@
             with
             | :? FileNotFoundException as ex -> "[ERROR] No file was found at " + ex.FileName
             | :? ArgumentException as ex -> "[ERROR] Invalid argument: " + ex.Message
-            | _ as ex -> ex.Message
+            | _ as ex -> ex.Message
+
+        let ``list-colours`` () =
+            printfn "[INFO.] Listing available colours..."
+            for item in colourList do
+                printfn "%s" item.Key
+            showEndOfCommandMessage