Merge pull request #18 from robinst/patch-1

README: Add rustup command for installing with nightly

README.md

@@ -59,8 +59,15 @@ Run `make` when any file changes, using the `.gitignore` file in the current dir
 
 ###Cargo (nightly Rust only)
 
+If you're running nightly Rust, install it using cargo:
+
     $ cargo install watchexec
 
+If you're using rustup, install it like this:
+
+    $ rustup toolchain install nightly
+    $ rustup run nightly cargo install watchexec
+
 ###OS X with Homebrew
 
     $ brew install https://raw.githubusercontent.com/mattgreen/watchexec/master/pkg/brew/watchexec.rb