由于EF版本和asp.net5版本不断更新导致命令出现冲突。最新命令如下：
C:\ScrumBasic\ScrumBasic>dnx ef
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Entity Framework Commands 7.0.0-rc1-16348
Usage: dnx ef [options] [command]
Options:
--version Show version information
-?|-h|--help Show help information
Commands:
database Commands to manage your database
dbcontext Commands to manage your DbContext types
migrations Commands to manage your migrations
dnx ef migrations add 【entityname】
dnx ef database update
原文：http://www.cnblogs.com/gilchen/p/5133482.html