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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/mvc/login-mvc-single-responsibility/user/model.go

@@ -0,0 +1,36 @@
+package user
+
+import (
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// Model is our User example model.
+type Model struct {
+	ID        int64  `json:"id"`
+	Firstname string `json:"firstname"`
+	Username  string `json:"username"`
+	// password is the client-given password
+	// which will not be stored anywhere in the server.
+	// It's here only for actions like registration and update password,
+	// because we caccept a Model instance
+	// inside the `DataSource#InsertOrUpdate` function.
+	password       string
+	HashedPassword []byte    `json:"-"`
+	CreatedAt      time.Time `json:"created_at"`
+}
+
+// GeneratePassword will generate a hashed password for us based on the
+// user's input.
+func GeneratePassword(userPassword string) ([]byte, error) {
+	return bcrypt.GenerateFromPassword([]byte(userPassword), bcrypt.DefaultCost)
+}
+
+// ValidatePassword will check if passwords are matched.
+func ValidatePassword(userPassword string, hashed []byte) (bool, error) {
+	if err := bcrypt.CompareHashAndPassword(hashed, []byte(userPassword)); err != nil {
+		return false, err
+	}
+	return true, nil
+}