fix #2645

  * refactor a bit #weekly_user_stats
  * pass 0 instead of "" to i18n
  * use the first week if none is provided

app/controllers/admins_controller.rb

@@ -30,20 +30,15 @@ class AdminsController < ApplicationController
   end
 
   def weekly_user_stats
+    @created_users_by_week = Hash.new{ |h,k| h[k] = [] }
     @created_users = User.where("username IS NOT NULL and created_at IS NOT NULL")
-    @created_users_by_week =  Hash.new{ |h,k| h[k] = [] }
     @created_users.find_each do |u|
-      unless u.nil?
-          @created_users_by_week[u.created_at.beginning_of_week.strftime("%Y-%m-%d")].push("#{u.username}")
-        end
-      end
-
-    unless(params[:week]).nil?
-      # @segment = "#{@created_users_by_week[(params[:week])]}"
-      @counter = "#{@created_users_by_week[(params[:week])].count}"
-    else
-      @counter = ""
+      week = u.created_at.beginning_of_week.strftime("%Y-%m-%d")
+      @created_users_by_week[week] << u.username
     end
+
+    @selected_week = params[:week] || @created_users_by_week.keys.first
+    @counter = @created_users_by_week[@selected_week].count
   end
 
   def stats

app/views/admins/weekly_user_stats.haml

-
 .span-24
-  = render :partial => 'admins/admin_bar'
+  = render partial: 'admins/admin_bar'
 %br
 %br
 
 .span-24.last
   %h2
-    = t('.current_server', :date => Time.now.to_date)
+    = t('.current_server', date: Time.now.to_date)
 
-= form_tag('/admins/weekly_user_stats', :method => 'get') do
-  = select_tag(:week, options_for_select(@created_users_by_week.keys))
+= form_tag('/admins/weekly_user_stats', method: 'get') do
+  = select_tag(:week, options_for_select(@created_users_by_week.keys), selected: @selected_week)
   = submit_tag t('admins.stats.go')
 
-= t('.amount_of', :count => @counter)
+= t('.amount_of', count: @counter)
 %br
-- @created_users_by_week[(params[:week])].each do |m|
+- @created_users_by_week[@selected_week].each do |m|
   = link_to m, "/u/#{m}"
   %br