Add feature "Sign up"

features/sign_up.feature

@@ -0,0 +1,11 @@
+Feature: Sign up
+  Background:
+    Given I visit sign up page
+
+  Scenario:
+    When I fill form with the following data:
+      | Email                | user@example.com |
+      | Пароль               | q1w2e3r4t5y6     |
+      | Подтверждение пароля | q1w2e3r4t5y6     |
+    And I click the form button "Регистрация"
+    Then I see main page

features/step_definitions/stepdefs.rb

@@ -4,6 +4,24 @@ When 'I visit main page' do
   visit '/'
 end
 
+When 'I visit sign up page' do
+  visit '/users/sign_up'
+end
+
+When 'I fill form with the following data:' do |table|
+  within 'form' do
+    table.rows.each do |(key, value)|
+      fill_in key, with: value
+    end
+  end
+end
+
+When 'I click the form button {string}' do |string|
+  within 'form' do
+    click_on string
+  end
+end
+
 Then 'I see main page' do
   expect(page).to have_css(
     'h1',