Add initial Linux CI build script

script/cibuild-atom-linux

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -e
+
+if [ -d /usr/local/share/nodenv ]; then
+  export NODENV_ROOT=/usr/local/share/nodenv
+  export PATH=/usr/local/share/nodenv/bin:/usr/local/share/nodenv/shims:$PATH
+  export NODENV_VERSION="v0.10.21"
+fi
+
+script/cibuild