st=>start: 跟着王总干 effort=>condition: 努力? gohome=>operation: 回老家去吧 success=>operation: 你的人生会很精彩

st->effort effort(yes)->success effort(no)->gohome

u A B has_and_belongs_to_many 多对多关联

Picture User Article has_many polymorphic:true多态关联，一个模型属于多个模型

尝试复杂形态的多态 User Dog Cat has_many Pets,polymorphic:true Pet < Dog Cat User hasmany Pet