Improve date picker UI

- Set first day of week to Monday
- Enable year and month selectors

#590

app/assets/javascripts/admin-manifest.coffee

@@ -9,6 +9,7 @@
 #= require jquery-ui/datepicker
 #= require select2
 #= require jquery.doubleScroll
+#= require datepicker
 #= require admin/application
 #= require admin/app
 #= require_tree ./admin

app/assets/javascripts/admin/datepicker.js

@@ -1,3 +0,0 @@
-$('.datepicker').datepicker({
-    dateFormat: 'yy-mm-dd'
-});

app/assets/javascripts/datepicker.js

@@ -0,0 +1,21 @@
+(function () {
+    $.datepicker.setDefaults({
+        changeMonth: true,
+        changeYear: true,
+        duration: 'fast',
+        firstDay: 1, // Monday
+        dateFormat: 'yy-mm-dd',
+    });
+
+    function attachDatePicker() {
+        var dateFields = $('.datepicker');
+        dateFields.datepicker();
+    }
+
+    // For turbolinks
+    document.addEventListener('page:change', function () {
+        attachDatePicker();
+    });
+
+    attachDatePicker();
+})();

app/assets/javascripts/registrant-manifest.coffee

@@ -8,7 +8,6 @@
 #= require shared/jquery.validate.bootstrap
 #= require jquery-ui/datepicker
 #= require select2
-
+#= require datepicker
 #= require shared/general
-
 #= require registrar/application

app/assets/javascripts/registrar-manifest.coffee

@@ -6,8 +6,7 @@
 #= require jquery.nested_attributes
 #= require jquery-ui/datepicker
 #= require select2
-
+#= require datepicker
 #= require shared/general
-
 #= require registrar/autocomplete
 #= require registrar/application

app/assets/javascripts/shared/general.coffee

@@ -21,10 +21,6 @@ $(document).on 'page:change', ->
   tomorrow = new Date(today)
   tomorrow.setDate(today.getDate() + 1)
 
-  $('.datepicker').datepicker(
-    dateFormat: "yy-mm-dd"
-  )
-
   if $('.js-combobox').length
     $('.js-combobox').select2
       width: "100%"