title: create two dimensional string array in golang
body: <p>I need to create a 2 dimensional string array as shown below - </p>
  
  <pre><code>matrix = [['cat,'cat','cat'],['dog','dog']]
  </code></pre>
  
  <p>Code:-</p>
  
  <pre><code>package main
  
  import (
      "fmt"
  )
  
  func main() {
      { // using append
  
      var matrix [][]string
      matrix[0] = append(matrix[0],'cat')
          fmt.Println(matrix)
      }
  }
  </code></pre>
  
  <p>Error:- </p>
  
  <pre><code>panic: runtime error: index out of range
  
  goroutine 1 [running]:
  main.main()
      /tmp/sandbox863026592/main.go:11 +0x20
  </code></pre>