Add Stashing Untracked Files to git til.

README.md

@@ -9,6 +9,7 @@ I shamelessly stole this idea from
 
 - [Intent To Add](git/intent-to-add.md)
 - [Staging Changes Within Vim](git/staging-changes-within-vim.md) 
+- [Stashing Untracked Files](git/stashing-untracked-files.md)
 - [Verbose Commit Message](git/verbose-commit-message.md)
 
 ## rails

git/stashing-untracked-files.md

@@ -0,0 +1,20 @@
+# Stashing Untracked Files
+
+Normally when stashing changes, using `git stash`, git is only going to
+stash changes to *tracked* files. If there are any new files in your project
+that aren't being tracked by git, they will just be left lying around.
+
+You might not want these *untracked* files left behind, polluting your
+working copy. Perhaps these files change your projects functionality or
+affect the outcome of tests. You just want them out of the way, for the
+moment at least.
+
+And so along comes the `-u` or `--untracked` flag.
+
+```bash
+$ touch new_file.rb
+$ git stash
+No local changes to stash
+$ git stash -u
+Saved working directory and index state WIP ...
+```