Db functions and event Schema w/ mongoose.

Create mongoose schema for Event and db.js to export ways we want to
interface with the database.

src/schemas/Event.js

@@ -0,0 +1,11 @@
+const mongoose = require('mongoose');
+const Schema = mongoose.Schema;
+
+const Event = new Schema({
+  date: Date,
+  isOk: Boolean,
+  message: String,
+  pdfFilename: String
+})
+
+module.exports = mongoose.model('Event', Event);