Part Add is buggy

[redknitin]

Expected Behavior

From the issue page, select the part and ensure that the UOM is correctly displayed. Enter the quantity and click the Add button.

Actual Behavior

From the issue page, select the part and ensure that the UOM is correctly displayed. Enter the quantity and click the Upload (supposed to be "Add") button. Error displayed is: "undefined method `find' for nil:NilClass" for tickets.rb:331 "check_existing = @rec[:parts].find { |x| x[:part] == @params[:code] }"

Steps to Reproduce

Attempt to add a part for an issue that has no existing parts.

[redknitin]

Most likely, all we need is a null check at tickets.rb:331