added some in models

app/models/user.rb

@@ -4,4 +4,12 @@ class User < ActiveRecord::Base
   has_many :votes
   devise :database_authenticatable, :registerable,
          :recoverable, :rememberable, :trackable, :validatable
+
+  validates :email 
+  validates :encrypted_password, presence: true 
+  validates :first_name, presence: true 
+  validates :last_name, presence: true
+  validates :birthday
+  validates :gender  
+       
 end

app/models/vote.rb

 class Vote < ActiveRecord::Base
   belongs_to :user
   belongs_to :candidate
+
+  validates :user_id, presence: true, uniqueness: true
+  validates :candidate_id, presence: true, uniqueness: true
+  validates :comments
 end

app/views/positions/_form.html.erb

+<%= simple_form_for(@position) do |p| %>
+	<%= p.input :name %>
+	<%= p.input :number_of_winners %>
+	
+
+<button class = "btn btn-success">Create new position <% p.submit %></button>
+
+<% end %>
+
+<%= link_to 'Cancel', positions_path, class: "btn btn-danger" %>
\ No newline at end of file

app/views/positions/new.html.erb

 <h1>New Position</h1>
 
-<%= form_for(@position) do |p| %>
-<p>
-	<%= p.label "Name" %>
-	<%= p.text_field :name %>
-</p>
-
-<p>
-	<%= p.label "Number of Winners" %>
-	<%= p.text_field :number_of_winners %>
-</p>
-
-<button class = "btn btn-success">Create new position <% p.submit %></button>
-
-<% end %>
-
-<%= link_to 'Cancel', positions_path, class: "btn btn-danger" %>
-
+<%= render "form"%>