namespace :proposals do
  desc "Updates all proposals by recalculating their hot_score"
  task touch: :environment do
    Proposal.find_in_batches do |proposals|
      proposals.each(&:save)
    end
  end

  desc "Import proposals from a xls file given an url"
  task :import, [:url] => :environment do |task, args|
    if args.url.blank?
      puts "Usage: rake proposals:import[url]"
    else
      ProposalXLSImporter.new(args.url).import
    end
  end
end

namespace :proposals do
  desc "Updates all proposals by recalculating their hot_score"
  task touch: :environment do
    Proposal.find_in_batches do |proposals|
      proposals.each(&:save)
    end
  end

  desc "Import proposals from a xls file given an url"
  task import: :environment do
    file_url = "#{Rails.root}/tmp/proposals.xlsx"
    ProposalXLSImporter.new(file_url).import
  end
end

--- 
+++ 
@@ -7,8 +7,11 @@
   end
 
   desc "Import proposals from a xls file given an url"
-  task import: :environment do
-    file_url = "#{Rails.root}/tmp/proposals.xlsx"
-    ProposalXLSImporter.new(file_url).import
+  task :import, [:url] => :environment do |task, args|
+    if args.url.blank?
+      puts "Usage: rake proposals:import[url]"
+    else
+      ProposalXLSImporter.new(args.url).import
+    end
   end
 end
Add url as a rake task parameter
