patch model&rpc (#207)

* change column to read from information_schema

* reactor generate mode from datasource

* reactor generate mode from datasource

* add primary key check logic

* resolve rebase conflicts

* add naming style

* add filename test case

* resolve rebase conflicts

* reactor test

* add test case

* change shell script to makefile

* update rpc new

* update gen_test.go

* format code

* format code

* update test

* generates alias

tools/goctl/model/sql/example/makefile

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# generate model with cache from ddl
+fromDDL:
+	goctl model mysql ddl -src="./sql/*.sql" -dir="./sql/model/user" -c
+
+
+# generate model with cache from data source
+user=root
+password=password
+datasource=127.0.0.1:3306
+database=gozero
+
+fromDataSource:
+	goctl model mysql datasource -url="$(user):$(password)@tcp($(datasource))/$(database)" -table="*" -dir ./model/cache -c -style camel