You may want to consider sending data in a different format. Something that will result in a hash like so: 
`params[:plate] == { description: "whatever", url: "other", location: "foo", price: "bar" }`
This will allow you to use ActiveRecords built in methods to create the plate with very little effort on the controllers side, like so:
`current_user.plates.create(params[:plate])`

This is one of the big wins for Rails "Convention over Configuration" mantra; and quite possibly the only thing I'll actually say I "like" about rails. Other than the income it's provided me for the past 2~3 years.

If 
If you're using rails 4, you'll want to extract a method that does the