Add a couple of Go questions

Also some contribution guidelines.

CONTRIBUTING.md

@@ -1 +1,17 @@
+## How to contribute
+
 Use pull requests to contribute to the project.
+
+Stick to the following format:
+
+<details>
+<summary>[Question]</summary><br><b>
+
+[Answer]
+</b></details>
+
+## What to avoid
+
+* Avoid adding installation questions. Those are the worst type of questions...
+* Don't copy questions and answers from other sources. They probably worked hard for adding them.
+* If you add new images, make sure they are free and can be used.

README.md

@@ -3,7 +3,7 @@
 
 :information_source:  This repository contains interview questions on various DevOps related topics
 
-:bar_chart:  There are currently **409** questions
+:bar_chart:  There are currently **413** questions
 
 
 :warning:  You don't need to know how to answer all the questions in this repo. DevOps is not about knowing all :)
@@ -2375,6 +2375,68 @@ It looks what unicode value is set at 101 and uses it for converting the integer
 If you want to get "101" you should use the package "strconv" and replace <code>y = string(x)</code> with <code>y = strconv.Itoa(x)</code>
 </b></details>
 
+<details>
+<summary>What is wrong with the following code?:
+
+```
+package main
+
+func main() {
+    var x = 2
+    var y = 3
+    const someConst = x + y
+}
+```
+</summary><br><b>
+</b></details>
+
+<details>
+<summary>What will be the output of the following block of code?:
+
+```
+package main
+
+import "fmt"
+
+const (
+	x = iota
+	y = iota
+)
+const z = iota
+
+func main() {
+	fmt.Printf("%v\n", x)
+	fmt.Printf("%v\n", y)
+	fmt.Printf("%v\n", z)
+}
+```
+</summary><br><b>
+</b></details>
+
+<details>
+<summary>What _ is used for in Go?</summary><br><b>
+</b></details>
+
+<details>
+<summary>What will be the output of the following block of code?:
+
+```
+package main
+
+import "fmt"
+
+const (
+	_ = iota + 3
+	x
+)
+
+func main() {
+	fmt.Printf("%v\n", x)
+}
+```
+</summary><br><b>
+</b></details>
+
 ## Mongo
 
 <a name="mongo-beginner"></a>