Merge pull request #500 from apaatsio/npm-autocompletion

npm autocompletion

completion/available/npm.completion.bash

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+# npm (Node Package Manager) completion
+
+if command -v npm &>/dev/null
+then
+  eval "$(npm completion)"
+fi