Add Manual HTTPS support

@@ -16,7 +16,8 @@ Monitor can be configured by passing options object into `expressMonitor` constr
 Default config:
 ```
 path: '/status',
-socketPort: 41338, // Port for Socket.io communication
+socketPort: 41338, // Port for Socket.io communication,
+useHttps: false,   // Force HTTPS protocol instead of HTTP
 spans: [{
   interval: 1,     // Every second
   retention: 60    // Keep 60 datapoints in memory

@@ -136,7 +136,7 @@
   Chart.defaults.global.elements.line.borderColor = "rgba(0,0,0,0.9)";
   Chart.defaults.global.elements.line.borderWidth = 2;
 
-  var socket = io(window.location.protocol + '//' + window.location.hostname + ':{{port}}');
+  var socket = io('{{protocol}}'+ '://' + window.location.hostname + ':{{port}}');
   var defaultSpan = 0;
   var spans = [];
 

@@ -10,6 +10,7 @@
   const defaultConfig = {
     socketPort: 41338,
     path: '/status',
+    useHttps: false,
     spans: [{
       interval: 1,
       retention: 60
@@ -85,7 +86,7 @@
     fs.readFile(path.join(__dirname, 'index.html'), 'utf8', (err,data) => {
       if (err) throw new Error(err);
     
-      var result = data.replace(/{{port}}/g, config.socketPort);
+      var result = data.replace(/{{port}}/g, config.socketPort).replace(/{{protocol}}/g, config.useHttps ? 'https' : 'http');
 
       fs.writeFile(path.join(__dirname, 'index.rendered.html'), result, 'utf8', (err) => {
         if (err) throw new Error(err);