upgrade: 数据类型识别，支持识别无符号类型

sql2go/parser.go

@@ -110,6 +110,10 @@ func generateTable(tableName string, modelStructName string, columnList []*sqlpa
 			"{COMMENT}":       comment,
 			"{TYPE}":          sqlTypeMap[item.Type.Type],
 		}
+		if item.Type.Unsigned {
+			// 无符号
+			data["{TYPE}"] = sqlTypeMap[item.Type.Type+" unsigned"]
+		}
 		/*if data["{FIELD}"] == "ID" {
 			basic.PrimaryFieldType = data["{TYPE}"]
 		}*/