fs.directory does not append a trailing '/' to directories

src/app/project.coffee

@@ -38,7 +38,7 @@ class Project
     fs.absolute filePath
 
   relativize: (fullPath) ->
-    fullPath.replace(@path, "")
+    fullPath.replace(@path, "").replace(/^\//, '')
 
   bufferWithId: (id) ->
     return buffer for buffer in @buffers when buffer.id == id

src/extensions/tree-view/add-dialog.coffee

@@ -21,7 +21,7 @@ class AddDialog extends View
     @miniEditor.on 'focusout', => @remove()
 
     directoryPath = if fs.isFile(@path) then fs.directory(@path) else @path
-    relativePath = @rootView.project.relativize(directoryPath)
+    relativePath = @rootView.project.relativize(directoryPath) + '/'
     @miniEditor.setText(relativePath)
 
   confirm: ->

src/stdlib/fs.coffee

@@ -22,9 +22,9 @@ module.exports =
   # non-directory component removed.
   directory: (path) ->
     if @isDirectory(path)
-      path.replace(/\/?$/, '/')
+      path.replace(/\/?$/, '')
     else
-      path.replace(new RegExp("/#{@base(path)}$"), '/')
+      path.replace(new RegExp("/#{@base(path)}$"), '')
 
   # Returns true if the file specified by path exists
   exists: (path) ->