Add methods push and shift

Author: AndriiKot

app3.js

@@ -0,0 +1,12 @@
+const arr = ['str1','str2',11,-4,true,false,101];
+
+console.log(arr);               // ['str1','str2',11,-4,true,false,101]
+console.log(arr[arr.length-1]);  //   101
+console.log(arr.at(-1));        //   101
+
+console.log(arr.shift());        //   'str1'
+console.log(arr);                //   ['str2',11,-4,true,false,101]
+
+console.log(arr.push(55));       //   7
+console.log(arr);                // ['str2',11,-4,true,false,101,55]
+