feat: subject of wordfflip

subjects/wordflip/README.md

@@ -0,0 +1,46 @@
+# WordFlip
+
+### Instructions
+
+Write a function `WordFlip()` that receives a string and returns it with the first and last words flipped.
+
+- Prints the Output followed by newline `\n`.
+- If the string is empty, return `Invalid Output`.
+- Ignore spaces if it's more then onr space in between words and all spaces in the edge of the words or sentences.
+
+### Expected function
+
+```go
+func WordFlip(str string) string {
+}
+```
+
+### Usage
+
+Here is a possible program to test your function:
+
+```go
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+    fmt.Print(WordFlip("First second last"))
+    fmt.Print(WordFlip(""))
+    fmt.Print(WordFlip("     ")) //all spaces
+    fmt.Print(WordFlip(" hello  all  of  you! "))
+
+}
+```
+
+And its output :
+
+```go
+$ go run . | cat -e
+last second First$
+Invalid Output$
+$
+you! of all hello$
+```