update readme

README.md

@@ -1,2 +1,47 @@
 # graph-php
 PHP library to build JS-less graphs
+
+### Calendar
+
+Build calendar graphs with unlimited chart layers
+
+#### [Month](https://github.com/YGGverse/graph-php/blob/main/src/Calendar/Month.php)
+
+##### Example
+
+
+###### Server-side
+
+```
+// Init current month
+$calendarMonth = new Yggverse\Graph\Calendar\Month(
+  time(),       // optional, custom timestamp
+  CAL_GREGORIAN // optional, define the calendar type (https://www.php.net/manual/en/calendar.constants.php)
+);
+
+// Let's build some random graphs for each day in this month
+foreach ($calendarMonth->getNodes() as $day => $node)
+{
+  // Register first layer data
+  $calendarMonth->addNode(
+    $day,          // required, number of day, on this example we are processing all of days in the initiated month
+    rand(1, 1000), // required, set some digit value for this day and current layer
+    'label 1',     // optional, label text that could be displayed on element over
+    'class-name',  // optional, customize output with CSS class
+    0              // optional, define chart layer if you want to build multiple charts in single day case
+                   // e.g. 1, 2, 3... or some keyword. first layer has 0 index by default.
+  );
+
+  // Make second layer for hourly stats in tis day...
+  for ($hour = 0; $hour < 24; $hour++)
+  {
+    // To build independent chart layer, make sure that layer attribute increased, for example to 1
+    $calendarMonth->addNode($day, rand(0, 1000), 'my hourly label 1, 'my-class-name-1', 1);
+    $calendarMonth->addNode($day, rand(0, 1000), 'my hourly label 1, 'my-class-name-1', 1);
+  }
+}
+```
+
+###### Client-side
+
+Coming soon on [YGGstate](https://github.com/YGGverse/YGGstate)