Added a long description to add

This explains mostly what the wrap option does, because it was not entirely clear

License: MIT
Signed-off-by: Richard Littauer <richard.littauer@gmail.com>

core/commands/add.go

@@ -36,6 +36,26 @@ Adds contents of <path> to ipfs. Use -r to add directories.
 Note that directories are added recursively, to form the ipfs
 MerkleDAG.
 `,
+		LongDescription: `
+Adds contents of <path> to ipfs. Use -r to add directories.
+Note that directories are added recursively, to form the ipfs
+MerkleDAG.
+
+The wrap option, '-w', wraps the file (or files, if using the
+recursive option) in a directory. This directory contains only
+the files which have been added, and means that the file retains
+its filename. For example:
+
+  > ipfs add example.jpg
+  added QmbFMke1KXqnYyBBWxB74N4c5SBnJMVAiMNRcGu6x1AwQH example.jpg
+  > ipfs add example.jpg -w
+  added QmbFMke1KXqnYyBBWxB74N4c5SBnJMVAiMNRcGu6x1AwQH example.jpg
+  added QmaG4FuMqEBnQNn3C8XJ5bpW8kLs7zq2ZXgHptJHbKDDVx
+
+You can now refer to the added file in a gateway, like so:
+
+  /ipfs/QmaG4FuMqEBnQNn3C8XJ5bpW8kLs7zq2ZXgHptJHbKDDVx/example.jpg
+`,
 	},
 
 	Arguments: []cmds.Argument{