Initial Commit, added 2 solutions

Author: Sar-Go

Diff for: go/0912-sort-an-array

@@ -0,0 +1,4 @@
+func sortArray(nums []int) []int {
+    sort.Ints(nums)
+    return nums
+}

Diff for: go/1929-concatenation-of-array

@@ -0,0 +1,13 @@
+func getConcatenation(nums []int) []int {
+  n := len(nums)
+	ans := make([]int, 2*n)	//lets make an array of int type and 2*n size
+
+	i := 0
+	for i < n {		//implementing for loop for the given condition
+		ans[i] = nums[i]
+		ans[i+n] = nums[i]
+		i++
+	}
+
+	return ans
+}