Add tasks for all the new languages

Task/Documentation/Swift/documentation.swift

@@ -0,0 +1,9 @@
+/**
+ Adds two numbers
+ :param: a an integer.
+ :param: b another integer.
+ :returns: the sum of a and b
+ */
+func add(a: Int, b: Int) -> Int {
+    return a + b
+}