Add feature test for setting weight of issue

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

features/project/issues/weight.feature

+Feature: Project Issues Weight
+  Background:
+    Given I sign in as a user
+    And I own project "Shop"
+    Given I visit project "Shop" issues page
+
+  Scenario: I should see labels list
+    Given I click link "New Issue"
+    And I submit new issue "500 error on profile" with weight
+    Then I should see issue "500 error on profile" with weight

features/steps/project/issues/weight.rb

+class Spinach::Features::ProjectIssuesWeight < Spinach::FeatureSteps
+  include SharedAuthentication
+  include SharedProject
+  include SharedPaths
+
+  step 'I click link "New Issue"' do
+    click_link "New Issue"
+  end
+
+  step 'I submit new issue "500 error on profile" with weight' do
+    fill_in "issue_title", with: "500 error on profile"
+    fill_in "issue_weight", with: 7
+    click_button "Submit new issue"
+  end
+
+  step 'I should see issue "500 error on profile" with weight' do
+    issue = Issue.find_by(title: "500 error on profile")
+
+    page.within '.weight' do
+      expect(page).to have_content '7'
+    end
+
+    expect(page).to have_content issue.title
+  end
+end