update for features

+ added flash/message assertions
+ adjusted urls to be http://google.com for tests for now
+ added @db-test tags to tests that use db interactions
+ added a scenario for duplicate URLs being used
+ added before and after steps to init and clean up db tests
+ added initialization of a test db for tests instead of interacting
  with the production database

features/homepage.feature

@@ -7,6 +7,7 @@ Feature: Homepage
   Scenario: Homepage Loads with a form
     Given I visit the "/" page
     Then I should see text "URL Shortener"
+    And I should see the message "Enter a URL"
     And I should see a form field "url"
     And I should see a "Submit" button
 
@@ -14,9 +15,21 @@ Feature: Homepage
     Given I visit the "/" page
     When I click the "Submit" button
     Then I should be on "/" page
+    And I should see the message "Please enter a valid URL"
 
+  @db-test
   Scenario: Submitting the form with a correct URL
     Given I visit the "/" page
-    When I type "http://google.com/" in the "url" field
+    When I type "http://google.com" in the "url" field
     And I click the "Submit" button
     Then I should be on "/create" page
+    And I should see the message "Link created"
+
+  @db-test
+  Scenario: Submitting the form with an existing URL
+    Given I visit the "/" page
+    And A link already exists with the url "http://google.com"
+    When I type "http://google.com" in the "url" field
+    And I click the "Submit" button
+    Then I should be on "/create" page
+    And I should see the message "Link exists"