Implement BMI calculation function and add example usage

Author: TTiamiyu

Sprint-2/3-mandatory-implement/1-bmi.js

@@ -15,5 +15,11 @@
 // It should return their Body Mass Index to 1 decimal place
 
 function calculateBMI(weight, height) {
+    const bmi = weight / (height * height);
+    return Math.round(bmi * 10) / 10;
+}
+
+console.log(calculateBMI(90, 1.85)); // should return 26.3
+
     // return the BMI of someone based off their weight and height
 }