add muletter.js binary

muletter.js

+#!/usr/bin/env node
+
+'use strict';
+
+const program = require('commander');
+const config = require('./package');
+console.error = (arg1, arg2) => console.warn(arg1?`\x1b[38;5;01m${arg1}\x1b[0m`:'', arg2? arg2:'');
+
+program
+  .description(config.description)
+  .usage('[options] [command] [argument]')
+  .version(config.version)
+  .command('init', 'Check config.yml, list.txt, body.(txt|html) and *.(jpg|png|pdf|zip...) as attachments ')
+  .command('send', 'Send the letter after running `init` command')
+  .on('--help', () => {
+    console.log('  Example of config.yml:', '\n');
+    console.log('    smtp_host: smtp.provider.com');
+    console.log('    smtp_user: username');
+    console.log('    smtp_password: 620f921w0212z4');
+    console.log('    letter_from: from@provider.com');
+    console.log('    letter_subject: this is the subject');
+    console.log('\n');
+  })
+  
+  .parse(process.argv);
+
+if (process.argv[2] === 'init') { 
+  process.exit();
+}
+
+if (process.argv[2] === 'send') { 
+  process.exit();
+}

package.json

 {
   "name": "muletter",
   "version": "0.1.0",
-  "description": "CLI mailer for small mailing list",
+  "description": "CLI newsletter for small mailing list",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/kimihub/muletter.git"
   },
   "keywords": [
     "letter",
+    "news",
     "mailer",
     "mailing",
     "email",
@@ -29,7 +30,8 @@
     "mulist": "muletter.js"
   },
   "engines": {
-    "node": ">= 0.6"
+    "node": ">= 4.0.0",
+    "npm": ">= 3.0.0"
   },
   "dependencies": {
     "commander": "^2.9.0"