Update README.md

Author: vtereshkov

README.md

@@ -1,2 +1,24 @@
-# umplot
-UmPlot: A plotting library for Umka
+# UmPlot
+UmPlot: A plotting library for [Umka](https://github.com/vtereshkov/umka-lang) based on [raylib](https://www.raylib.com).
+
+## Example
+```
+import "umplot.um"
+
+fn main() {
+    plt := umplot.init(4)
+
+    for x := 0.0; x <= 100.0; x += 1.0 {
+        for i := 0; i < 4; i++ {
+            y := (1 + 0.5 * i) * sin(x / 10.0 + i)
+            plt.series[i].add(x, y)
+        }
+    }
+
+    plt.series[1].style.kind = umplot.STYLE_SCATTER
+
+    plt.plot()
+}
+```
+![](umplot.png)
+