Change default button class to "success button"

Remove radius(no longer used) and small(too small)

README.md

@@ -137,7 +137,7 @@ an additional p element will be added after the input element:
 
 ### Submit Button
 
-The 'submit' helper wraps the rails helper and sets the class attribute to "small radius success button" by default.
+The 'submit' helper wraps the rails helper and sets the class attribute to "success button" by default.
 
 ```ruby
 f.submit

lib/foundation_rails_helper/configuration.rb

@@ -20,7 +20,7 @@ class Configuration
     attr_accessor :ignored_flash_keys
 
     def initialize
-      @button_class = 'small radius success button'
+      @button_class = 'success button'
       @ignored_flash_keys = []
     end
   end

spec/foundation_rails_helper/configuration_spec.rb

@@ -3,9 +3,9 @@
 describe FoundationRailsHelper do
   describe FoundationRailsHelper::Configuration do
     describe "#button_class" do
-      it "default value is 'small radius success button'" do
+      it "default value is 'success button'" do
         config = FoundationRailsHelper::Configuration.new
-        expect(config.button_class).to eq('small radius success button')
+        expect(config.button_class).to eq('success button')
       end
     end
 
@@ -41,7 +41,7 @@
         FoundationRailsHelper.reset
 
         config = FoundationRailsHelper.configuration
-        expect(config.button_class).to eq('small radius success button')
+        expect(config.button_class).to eq('success button')
       end
 
       it "resets the configured ignored flash keys" do

spec/foundation_rails_helper/form_builder_spec.rb

@@ -682,7 +682,7 @@
       it "should display form button with default class" do
         form_for(@author) do |builder|
           node = Capybara.string builder.submit('Save')
-          expect(node).to have_css('input[type="submit"][class="small radius success button"]')
+          expect(node).to have_css('input[type="submit"][class="success button"]')
         end
       end
     end