Add all the A tasks

Task/Associative-array-Creation/Go/associative-array-creation.go

@@ -0,0 +1,16 @@
+// declare a nil map variable, for maps from string to int
+var x map[string] int
+
+// make an empty map
+x = make(map[string] int)
+
+// make an empty map with an initial capacity
+x = make(map[string] int, 42)
+
+// set a value
+x["foo"] = 3
+
+// make a map with a literal
+x = map[string] int {
+  "foo": 2, "bar": 42, "baz": -1,
+}