在 new.html.erb
`<div>
<%= f.check_box :hobby, {:multiple => "true"}, "hockeys", nil %>
<%= f.label :hockeys %>
<%= f.check_box :hobby, {:multiple => "true"}, "cricket", nil %>
<%= f.label :cricket %>
</div>`
在 show.html.erb
<%@rteacher.hobby%>
输出(如果我选择多个复选框)
`---""hobby"--""cricket`