Feature/add sum

package.json

@@ -0,0 +1,20 @@
+{
+  "name": "javascript-calculator",
+  "version": "1.0.0",
+  "description": "From zero to FullStack - an unofficial course led by [Pedro Soares](https://github.com/pncsoares) with the aim of guiding and helping two friends to learn programming and become software developers.",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/from-zero-to-fullstack/javascript-calculator.git"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/from-zero-to-fullstack/javascript-calculator/issues"
+  },
+  "homepage": "https://github.com/from-zero-to-fullstack/javascript-calculator#readme"
+}

src/sum-two-numbers.js

@@ -0,0 +1,11 @@
+
+// to store input numbers
+const num1 = 5;
+const num2 = 10;
+
+function sum(num1, num2) {
+    return num1 + num2;
+}
+
+const x = sum(num1, num2);
+console.log(x);