Add organisations page, controller and merge model

app/controllers/merge_controller.rb

@@ -0,0 +1,42 @@
+class MergeController < ApplicationController
+  before_action :authenticate_user!
+
+  def show
+    render form.view_path
+  end
+
+  def update
+    if form.valid? && form.save!
+      redirect_to form.next_path
+    else
+      render form.view_path
+    end
+  end
+
+  def organisations
+    @answer_options = answer_options
+    @merge = Merge.new(form_params)
+    @merging_organisations_list = Organisation.where(id: @merge.merging_organisations)
+  end
+
+  def answer_options
+    answer_options = { "" => "Select an option" }
+
+    Organisation.all.pluck(:id, :name).each do |organisation|
+      answer_options[organisation[0]] = organisation[1]
+    end
+    answer_options
+  end
+
+private
+
+  def form_params
+    merge_params = params.fetch(:merge, {}).permit(:merging_organisations)
+    if merge_params[:merging_organisations].blank?
+      merge_params[:merging_organisations] = [params[:id]]
+    else
+      merge_params[:merging_organisations] = merge_params[:merging_organisations].split(" ") << params[:merge][:merging_organisation]
+    end
+    merge_params
+  end
+end

app/models/merge.rb

@@ -0,0 +1,6 @@
+class Merge
+  include ActiveModel::Model
+  include ActiveModel::Attributes
+
+  attribute :merging_organisations, array: true, default: []
+end

app/views/merge/organisations.html.erb

@@ -0,0 +1,41 @@
+<% title = "Tell us if your organisation is merging" %>
+<% content_for :title, title %>
+
+<%= govuk_back_link href: organisation_path %>
+<h2 class="govuk-heading-l">Tell us if your organisation is merging</h2>
+
+<div class="govuk-grid-row">
+  <div class="govuk-grid-column-two-thirds-from-desktop">
+   <p class="govuk-body">Start typing to search for your managing agent</p>
+
+<%= form_with model: @merge, url: merge_organisations_organisation_path, method: :patch do |f| %>
+  <%= f.govuk_error_summary %>
+
+  <%= render partial: "organisation_relationships/related_organisation_select_question", locals: {
+    field: :merging_organisation,
+    question: Form::Question.new("", { "answer_options" => @answer_options }, nil),
+    f:,
+  } %>
+  <%= f.hidden_field :merging_organisations %>
+  <%= f.govuk_submit "Add organisation", classes: "govuk-button--secondary" %>
+  <%= govuk_table do |table| %>
+  <% @merging_organisations_list.each do |merging_organisation| %>
+      <%= table.body do |body| %>
+        <%= body.row do |row| %>
+          <% row.cell(text: merging_organisation.name) %>
+          <% if current_user.data_coordinator? || current_user.support? %>
+            <% row.cell(html_attributes: {
+              scope: "row",
+              class: "govuk-!-text-align-right",
+            }) do %>
+              <%= govuk_link_to("Remove", merge_organisations_organisation_path) %>
+            <% end %>
+          <% end %>
+        <% end %>
+      <% end %>
+    <% end %>
+  <% end %>
+<% end %>
+
+<%= govuk_button_link_to "Continue", merge_organisations_organisation_path, button: true %>
+</div>