Change src directory to use mediator pattern

src/cli.js

@@ -0,0 +1,32 @@
+#!/usr/bin/env node
+
+'use strict'
+
+const yargs = require('yargs')
+
+module.exports = () =>
+  yargs
+    .scriptName('oasis')
+    .env('OASIS')
+    .usage('Usage: $0 [options]')
+    .options('open', {
+      describe: 'Automatically open app in web browser',
+      default: true,
+      type: 'boolean'
+    })
+    .options('host', {
+      describe: 'Hostname for web app to listen on',
+      default: 'localhost',
+      type: 'string'
+    })
+    .options('port', {
+      describe: 'Port for web app to listen on',
+      default: 3000,
+      type: 'number'
+    })
+    .options('debug', {
+      describe: 'Use verbose output for debugging',
+      default: false,
+      type: 'boolean'
+    })
+    .argv