Update README.md
Add Redhat instructions.  Remove bit about installing xi-core which is no longer necessary.
@@ -11,14 +11,10 @@ gxi is a work in progress!
sudo apt-get install libgtk-3-dev
```
-### Installing xi-core
-
-xi-core must be executable from your `PATH`.
+### Installing dependencies on Redhat
```sh
-git clone https://github.com/google/xi-editor.git
-cd xi-editor/rust
-cargo install
+sudo yum install gtk3-devel
```
### Running gxi
