fix vimrc path and update Readme

Readme.md

@@ -10,10 +10,10 @@ Therefore, each package may have a subdirectory containing any of:
    * system
    * user
 
-*Example*:
+*Example* with dotfiles repo checked out to `./dotfiles` (`DOTFILES_DIR`):
 
 ```plain
-dotfiles
+./dotfiles
 ├── Readme.md
 ├── ssh
 │   ├── system
@@ -53,7 +53,7 @@ All directories under the user target are relative to `$HOME`.
 On GNU compatible system this is equivalent to:
 
 ```bash
-stow -d $DOTFILES_DIR/vim -t /home/acme
+stow -d "$DOTFILES_DIR" -t "/home/$USER" vim
 ```
 
 ## System
@@ -68,7 +68,7 @@ All directories under the system targt are relative to `/`.
 On GNU compatible system this is equivalent to:
 
 ```bash
-stow -d $DOTFILES_DIR/ssh/user -t /home/acme
-sudo stow -d $DOTFILES_DIR/ssh/system -t /
+stow -d "$DOTFILES_DIR/ssh" -t "/home/$USER" user
+sudo stow -d "$DOTFILES_DIR/ssh" -t / system
 ```