I was using content_tag(:input) and didn't give it space for the value spot.
Throws: ** (ArgumentError) lists in Phoenix.HTML and templates may only contain integers representing bytes, binaries or other lists, got invalid entry:
<%= content_tag :input, value: @item.quantity, type: "value", class: "input-xlarge", id: "orderQuantity" %>
works
<%= content_tag :input, "", value: @item.quantity, type: "value", class: "input-xlarge", id: "orderQuantity" %>