Merge pull request #92 from tacaswell/doc_arch_install

DOC: add install instructions for Arch linux and RHEL

README.md

@@ -96,6 +96,8 @@ Plug in the USB drive and boot to the live image. Configure networking to contin
 
 Install several packages required for the following steps:
 
+**debian and ubuntu**
+
 ```console
 $ sudo apt-get update
 
@@ -107,6 +109,17 @@ $ sudo apt-get install -y \
      secure-delete
 ```
 
+**Arch Linux**
+
+```console
+$ sudo pacman -Syu gnupg2 pcsclite ccid yubikey-personalization
+```
+
+**RHEL7**
+```console
+$ sudo yum install -y gnupg2 pinentry-curses pcsc-lite pcsc-lite-libs gnupg2-smime
+```
+
 You may also need more recent versions of [yubikey-personalization](https://developers.yubico.com/yubikey-personalization/Releases/) and [yubico-c](https://developers.yubico.com/yubico-c/Releases/).
 
 **macOS** Download and install [Homebrew](https://brew.sh/) and the following Brew packages - `gnupg yubikey-personalization hopenpgp-tools ykman pinentry-mac`