Add usage notes

And  simplify  .gitignore.   I  originally added  !/.*  to  make  sure
committed dotfiles  would still appear  in git status, but  that's not
necessary:

> Files already tracked by Git are not affected
> ― gitignore(5)

The only downside is that to start tracking new dotfiles, git add will
need --force.

1 files changed, 25 insertions, 2 deletions

diff --git a/README b/README
index a7e840d..2e537e5 100644
--- a/README
+++ b/README
@@ -1,4 +1,27 @@
-What's "dotfiles", precious?
-What's "dotfiles" eh?
+A few good dotfiles
+===================
 
 🎜 Clone'em, tweak'em, stick'em in your $HOME 🎝
+
+Usage notes
+-----------
+
+Some Git sorcery to maximize usability and avoid brittle hacks
+(e.g. symlinks, homebrewed synchronization scripts):
+
+``` sh
+# In $HOME, prepare a Git repository:
+$ git init
+
+# Grab history:
+$ git remote add --fetch $cutename $url
+
+# Move to latest commit without actually touching files:
+$ git reset $cutename/master
+
+# Checkout dotfiles that were not already in $HOME:
+$ git checkout -- .gitignore # …
+
+# Tell Git to forget about repository fluff:
+$ git update-index --assumed-unchanged -- README # …
+```