Use dotenv to load environment variables from .env file

.gitignore

@@ -1,3 +1,2 @@
-smtp-credentials.json
 node_modules
-.local-run.sh
+.env

package-lock.json

@@ -136,6 +136,11 @@
       "resolved": "https://registry.npmjs.org/destroy/-/destroy-1.0.4.tgz",
       "integrity": "sha1-l4hXRCxEdJ5CBmE+N5RiBYJqvYA="
     },
+    "dotenv": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/dotenv/-/dotenv-5.0.0.tgz",
+      "integrity": "sha512-p4A7snaxI9Hnj3GDWhTpckHYcd9WwZDmGPcvJJV3CoRFq0Dvsp96eYgXBl9WbmbJfuxqiZ2WenNaeWSs675ghQ=="
+    },
     "ee-first": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/ee-first/-/ee-first-1.1.1.tgz",

package.json

@@ -3,6 +3,7 @@
     "body-parser": "^1.18.2",
     "client-oauth2": "^4.1.0",
     "client-sessions": "^0.8.0",
+    "dotenv": "^5.0.0",
     "express": "^4.16.2",
     "nodemailer": "^4.4.0",
     "popsicle": "^9.2.0"

server.js

@@ -1,5 +1,6 @@
 "use strict";
 
+require("dotenv").load();
 const express = require("express");
 const bodyParser = require("body-parser");
 const nodemailer = require("nodemailer");