cmd/upspin-ui: add basic usage documentation

Change-Id: I7081e78777f77fe4fe8f00e0c0648d6e62644159
Reviewed-on: https://upspin-review.googlesource.com/14821
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/cmd/upspin-ui/doc.go b/cmd/upspin-ui/doc.go
new file mode 100644
index 0000000..e0cc5af
--- /dev/null
+++ b/cmd/upspin-ui/doc.go
@@ -0,0 +1,48 @@
+// Copyright 2017 The Upspin Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Command upspin-ui presents a web interface to the Upspin name space,
+and also provides a facility to sign up an Upspin user and deploy
+an upspinserver to Google Cloud Platform.
+It operates as the user in the specified config.
+If no config is available at the specified path,
+the user is prompted to sign up an Upspin user.
+
+Browser features
+
+The Upspin browser presents two navigation panes.
+
+Each browser pane lists the contents of an Upspin directory.
+The directory is shown in a text box at the top of each pane.
+
+You can navigate directly to a specific Upspin path by typing (or pasting) it
+into the text box and pressing the enter key.
+The button to the left of the text box navigates to the parent of the current
+directory.
+
+Clicking the name of an entry will attempt to download the entry with your web
+browser or, if the entry is a directory, will navigate to that directory.
+
+At startup, the left pane displays the current user's root and the right pane
+displays the path augie@upspin.io.
+
+The checkboxes beside each entry permit the (de-)selection of entries.
+The checkbox at the top of each list of entries (de-)selects all entries in
+that directory.
+
+The "Delete" button recursively deletes the selected files and directories.
+
+The "Copy" button recurisively copies the selected files and directories to
+the directory displayed in the opposite pane.
+
+The "Make directory" button creates a directory in the pane's current
+directory.
+
+The "Refresh" button reloads the contents of the directory and displays it.
+
+The info buttons (a little "i" in a circle, to the right of each file) display
+extended information for a given directory entry.
+*/
+package main
diff --git a/cmd/upspin-ui/main.go b/cmd/upspin-ui/main.go
index db7189d..62726b1 100644
--- a/cmd/upspin-ui/main.go
+++ b/cmd/upspin-ui/main.go
@@ -2,18 +2,14 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Command browser presents a web interface to the Upspin name space.
-// It operates as the user in the specified config.
-// It is still in its early stages of development and should be used with care.
 package main // import "augie.upspin.io/cmd/upspin-ui"
 
 // TODO(adg): Flesh out the inspector (show blocks, etc).
-// TODO(adg): Drag and drop support.
-// TODO(adg): Secure the web UI; only allow the local user to access it.
 // TODO(adg): Update the URL in the browser window to reflect the UI.
 // TODO(adg): Facility to add/edit Access files in UI.
 // TODO(adg): Awareness of Access files during copy and remove.
 // TODO(adg): Show progress of removes/copies in the user interface.
+// TODO(adg): Display links and handle their navigation properly.
 
 import (
 	"crypto/rand"