Add button to create sessions from school

This adds a button that allows users to create sessions directly from
the school page, skipping the steps where you need to choose the school.

Jira-Issue: MAV-2645

Author: thomasleese

app/controllers/draft_sessions_controller.rb

@@ -188,7 +188,7 @@ def set_back_link_path
       elsif @draft_session.editing?
         wizard_path("confirm")
       elsif current_step == @draft_session.wizard_steps.first
-        schools_path
+        @draft_session.return_to == "school" ? schools_path : sessions_path
       else
         previous_wizard_path
       end

app/controllers/sessions_controller.rb

@@ -30,9 +30,18 @@ def new
     @draft_session.clear_attributes
     @draft_session.assign_attributes(create_params)
 
+    if params[:school_id].present?
+      @draft_session.location_type = "school"
+      @draft_session.location_id = params[:school_id]
+      @draft_session.return_to = "school"
+    else
+      @draft_session.return_to = "sessions"
+    end
+
     @draft_session.save!
 
-    redirect_to draft_session_path(Wicked::FIRST_STEP)
+    first_step = params[:school_id].present? ? "programmes" : Wicked::FIRST_STEP
+    redirect_to draft_session_path(first_step)
   end
 
   def show

app/views/schools/sessions.html.erb

@@ -8,6 +8,8 @@
 
 <%= render "header" %>
 
+<%= govuk_button_link_to "Add a new session", new_session_path(school_id: @location.id), secondary: true %>
+
 <% if @scheduled_sessions.present? %>
   <h3 class="nhsuk-heading-m">Scheduled sessions</h3>