reorganization of _examples and add some new examples such as iris+groupcache+mysql+docker

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/bootstrap/routes/following.go

@@ -0,0 +1,11 @@
+package routes
+
+import (
+	"github.com/kataras/iris/v12"
+)
+
+// GetFollowingHandler handles the GET: /following/{id}
+func GetFollowingHandler(ctx iris.Context) {
+	id, _ := ctx.Params().GetInt64("id")
+	ctx.Writef("from "+ctx.GetCurrentRoute().Path()+" with ID: %d", id)
+}