expanded click button to click any button for easier use

features/homepage.feature

@@ -12,6 +12,6 @@ Feature: Homepage
 
   Scenario: Submitting the form without entering a URL
     Given I visit the '/' page
-    When I click the submit button
+    When I click the "Submit" button
     Then I should be on "/" page
 

features/step_definitions/steps.rb

@@ -6,8 +6,8 @@ end
 
 # WHEN
 
-When('I click the submit button') do 
-  click_button "Submit"
+When('I click the {string} button') do |string|
+  click_button {string}
 end
 
 # THEN