added snippet for calculating nth fibonacci number

Author: Mcbencrafter

snippets/java/math/fibonacci.md

@@ -0,0 +1,19 @@
+---
+title: Fibonacci
+description: Calculates the nth fibonacci number
+author: Mcbencrafter
+tags: math,number,fibonacci
+---
+
+```java
+public static int fibonacci(int number) {
+    if (number <= 1) 
+        return number;
+        
+    return fibonacci(number - 1) + fibonacci(number - 2);
+}
+
+// Usage:
+int number = 5;
+System.out.println(fibonacci(number)) // 3 (0, 1, 1, 2, 3)
+```