Update the README with usage of the library

README.md

@@ -3,3 +3,20 @@
 ![Preview image](preview.svg)
 
 </div>
+
+# NOTE: This library is still in initial phases of development
+
+### build.gradle[.kts]
+```groovy
+implementation("ir.mahozad.android:pie-chart:0.1.0")
+```
+
+### layout.xml
+```xml
+<ir.mahozad.android.PieChart
+    android:id="@+id/pieChart"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    app:holeRatio="0.3"
+    app:gap="8dp" />
+```