Update document

doc/SUMMARY.md

@@ -1,6 +1,7 @@
 # Summary
 
-* [GORM GITHUB](http://github.com/jinzhu/gorm)
+* [GORM Guides](http://github.com/jinzhu/gorm)
+
 * [Getting Started with GORM](README.md)
 {% for path, chapter in book.chapters %}
 * [{{ chapter.name }}]({{ path }})

doc/models/defination.md

@@ -0,0 +1,81 @@
+# Models
+
+<!-- toc -->
+
+## Model Defination
+
+```go
+type User struct {
+	ID           int
+	Birthday     time.Time
+	Age          int
+	Name         string  `sql:"size:255"` // Default size for string is 255, you could reset it with this tag
+	Num          int     `sql:"AUTO_INCREMENT"`
+	CreatedAt    time.Time
+	UpdatedAt    time.Time
+	DeletedAt    *time.Time
+	IgnoreMe     int `sql:"-"`   // Ignore this field
+}
+```
+
+## Conventions & Overriding Conventions
+
+### Table name is the pluralized version of struct name
+
+```go
+type User struct {} // default table name is `users`
+
+// set User's table name to be `profiles
+type (User) TableName() string {
+  return "profiles"
+}
+
+// Or disable table name's pluralization globally
+db.SingularTable(true) // if set this to true, then default table name will be `user`, table name setted with `TableName` won't be affected
+```
+
+### Column name is the snake case of field's name
+
+```go
+type User struct {
+  ID uint             // column name will be `id`
+  Name string         // column name will be `name`
+  Birthday time.Time  // column name will be `birthday`
+  CreatedAt time.Time // column name will be `created_at`
+}
+
+type Animal struct {
+	AnimalId    int64     `gorm:"column:beast_id"` // set column name to be `beast_id`
+	Birthday    time.Time `gorm:"column:day_of_the_beast"` // set column name to be `day_of_the_beast`
+	Age         int64     `gorm:"column:age_of_the_beast"` // set column name to be `age_of_the_beast`
+}
+```
+
+### Default use field `ID` as primary key
+
+```go
+type User struct {
+  ID uint  // field `ID` is the default primary key for `User`
+  Name string
+}
+
+type Animal struct {
+  // tag `primary_key` used to set `AnimalId` to be primary key
+  AnimalId int64 `gorm:"primary_key"`
+  Name     string
+  Age      int64
+}
+```
+
+### Use `CreatedAt` to store record's created time if field exists
+
+```go
+db.Create(&user) // will set field `CreatedAt`'s time to time now
+
+// If you want to change its value, use `Update`
+db.Model(&user).Update("CreatedAt", time.Now())
+```
+
+### Use `UpdatedAt` to store record's updated time if field exists
+### Use `DeletedAt` to store record's deleted time if field exists
+### Gorm provide a default model struct, you could embed it in your struct