Add markdown widget for interactive app forms

Allows inserting arbitrary Markdown into the app forms through the
form.yml files.

apps/dashboard/app/helpers/batch_connect/session_contexts_helper.rb

@@ -35,6 +35,8 @@ def create_widget(form, attrib, format: nil, hide_excludable: true, hide_fixed:
       end
     when 'file_attachments'
       render :partial => "batch_connect/session_contexts/file_attachments", :locals => { form: form, attrib: attrib, field_options: field_options }
+    when 'markdown'
+      OodAppkit.markdown.render(attrib.value.to_s).html_safe
     else
       form.send widget, attrib.id, all_options
     end

apps/dashboard/app/lib/smart_attributes/attribute.rb

@@ -68,6 +68,10 @@ def widget
       (opts[:widget] || 'text_field').to_s
     end
 
+    def serialize?
+      !!opts.fetch(:serialize, widget != "markdown")
+    end
+
     # Form label for this attribute
     # @param fmt [String, nil] formatting of form label
     # @return [String] form label

apps/dashboard/app/models/batch_connect/session_context.rb

@@ -14,7 +14,7 @@ class SessionContext
     # Attributes used for serialization
     # @return [Hash{String => String, nil}] attributes to be serialized
     def attributes
-      @attributes.reject(&:fixed?).map { |a| [a.id.to_s, nil] }.to_h
+      @attributes.reject(&:fixed?).select(&:serialize?).map { |a| [a.id.to_s, nil] }.to_h
     end
 
     def attributes=(params = {})
@@ -69,7 +69,7 @@ def update_with_cache(cache)
     end
 
     def to_h
-      Hash[*map { |a| [a.id.to_sym, a.value] }.flatten]
+      Hash[*select(&:serialize?).map { |a| [a.id.to_sym, a.value] }.flatten]
     end
 
     def to_openstruct(addons: {})

apps/dashboard/app/models/batch_connect/settings.rb

@@ -18,12 +18,12 @@ def app
     def outdated?
       outdated = false
       # CHECK IF THERE ARE NEW ATTRIBUTES NOT IN THE VALUES HASH
-      app.attributes.each do |attribute|
+      app.attributes.select(&:serialize?).each do |attribute|
         outdated = true unless values.key?(attribute.id.to_sym)
       end
       # CHECK IF THERE ARE OLD VALUES NO LONGER IN THE APP ATTRIBUTES STILL IN THE VALUES HASH
       values.each_key do |attribute_id|
-        outdated = true if app.attributes.select { |attribute| attribute.id.to_sym == attribute_id }.empty?
+        outdated = true if app.attributes.select(&:serialize?).select { |attribute| attribute.id.to_sym == attribute_id }.empty?
       end
 
       outdated

apps/dashboard/app/views/batch_connect/settings/show.html.erb

@@ -68,7 +68,7 @@ locals: {
             end
           %>
         </div>
-        <% @settings.app.attributes.each do |attribute| %>
+        <% @settings.app.attributes.select(&:serialize?).each do |attribute| %>
           <p>
             <strong><%= attribute.label %>:</strong>
             <span><%= @settings.values[attribute.id.to_sym] %></span>