goctl model reactor (#15)

* reactor sql generation

* reactor sql generation

* add console & example

* optimize unit test & add document

* modify default config

* remove test file

* Revert "remove test file"

This reverts commit 81041f9e

* fix stringx.go & optimize example

* remove unused code

tools/goctl/model/sql/parser/error.go

@@ -0,0 +1,11 @@
+package parser
+
+import (
+	"errors"
+)
+
+var (
+	unSupportDDL        = errors.New("unexpected type")
+	tableBodyIsNotFound = errors.New("create table spec not found")
+	errPrimaryKey       = errors.New("unexpected joint primary key")
+)