create slack service, try to create invites with slack api and if it fails then send the emails to configured channel

services/slack.js

@@ -0,0 +1,55 @@
+'use strict';
+
+var request = require('superagent');
+var config = require('../lib/config');
+var Promise = require('bluebird');
+
+module.exports = {
+
+  /**
+   * Create a new Slack - invite
+   */
+
+  createInvite: function(email) {
+    return new Promise(function(resolve, reject) {
+      request
+      .post('https://koodiklinikka.slack.com/api/users.admin.invite')
+      .field('email', email)
+      .field('channels', config.slack.channels)
+      .field('token', config.slack.token)
+      .field('set_active', 'true')
+      .end(function(error, response){
+
+        if(!response.body.ok) {
+          return reject(response.body.error);
+        }
+
+        if(error) {
+          return reject(error);
+        }
+
+        resolve(response.body);
+      });
+    });
+  },
+
+  /**
+   * Send a message to configured channel
+   */
+
+  createMessage: function(message) {
+    return new Promise(function(resolve, reject) {
+      request
+      .post('https://koodiklinikka.slack.com/api/chat.postMessage')
+      .field('text', message)
+      .field('channel', config.slack.channels)
+      .field('token', config.slack.token)
+      .end(function(error, response){
+        if(error) {
+          reject(error);
+        }
+        resolve(response.body);
+      });
+    });
+  }
+};