Refs #12: show validation error

app/controllers/authors_controller.rb

@@ -7,12 +7,17 @@ def show
     @author = Author.find(params[:id])
   end
 
-  def new; end
+  def new
+    @author = Author.new
+  end
 
   def create
     @author = Author.new(params.require(:author).permit(:first_name, :last_name, :homepage))
 
-    @author.save
-    redirect_to @author
+    if @author.save
+      redirect_to @author
+    else
+      render 'new'
+    end
   end
 end

app/views/authors/new.html.erb

@@ -1,4 +1,19 @@
 <%= form_for :author, url: authors_path do |f| %>
+
+    <% if @author.errors.any? %>
+        <div id="error_explanation">
+          <h2>
+            <%= pluralize(@author.errors.count, 'error') %> prohibited
+            this author from being saved:
+          </h2>
+          <ul>
+            <% @author.errors.full_messages.each do |msg| %>
+                <li><%= msg %></li>
+            <% end %>
+          </ul>
+        </div>
+    <% end %>
+
     <p>
       <%= f.label :first_name %><br>
       <%= f.text_field :first_name %>