Update GettingStarted.md

GettingStarted.md

@@ -18,46 +18,50 @@ When combined into a single operation, this is called a *purchase*.
 
 All of these operations are performed on an instance of a Gateway subclass:
 
-    gateway = SomeGateway.new
+```ruby
+gateway = SomeGateway.new
 
-	# Amounts are always specified in cents, so this is
-	# equal to $10.
-	response = gateway.purchase(1000, credit_card)
+# Amounts are always specified in cents, so $10.00 is 1000 cents
+response = gateway.purchase(1000, credit_card)
+```
 
-Both `#authorize`, `#capture` and `#purchase` return a {ActiveMerchant::Billing::Response} instance.
+All three `#authorize`, `#capture` and `#purchase` methods return a `ActiveMerchant::Billing::Response` instance.
 This object contains the details of the operation, most notably whether it was successful.
 
-    if response.success?
-	  puts "Payment complete!"
-    else
-	  puts "Payment failed: #{response.message}"
-	end
-
-As can be seen, {ActiveMerchant::Billing::Response#success?} returns whether the operation completed
-successfully. If `false`, the error message is available in `#message`.
+```ruby
+if response.success?
+  puts "Payment complete!"
+else
+  puts "Payment failed: #{response.message}"
+end
+```
 
 ## Handling Credit Cards
 
-In Active Merchant, credit cards are represented by instances of {ActiveMerchant::Billing::CreditCard}.
+In Active Merchant, credit cards are represented by instances of `ActiveMerchant::Billing::CreditCard`.
 Instantiating such an object is simple:
 
-	credit_card = ActiveMerchant::Billing::CreditCard.new(
-      :first_name => 'Steve',
-      :last_name  => 'Smith',
-      :month      => '9',
-      :year       => '2014',
-      :type       => 'visa',
-      :number     => '4242424242424242')
+```ruby
+credit_card = ActiveMerchant::Billing::CreditCard.new(
+  :first_name => 'Steve',
+  :last_name  => 'Smith',
+  :month      => '9',
+  :year       => '2014',
+  :type       => 'visa',
+  :number     => '4242424242424242')
+```
 
 Most often, though, you'll be using user-supplied data. In a typical Rails controller:
 
-    credit_card = ActiveMerchant::Billing::CreditCard.new(params[:credit_card])
+```ruby
+credit_card = ActiveMerchant::Billing::CreditCard.new(params[:credit_card])
+```
 
 ### Validation
 
 While the above attributes are always required for a `CreditCard` to be valid, some gateways also
 require a *verification value*, e.g. a CVV code, to be given.
 
-Validating a credit card is as simple as calling `#valid?`, which
+Validating a credit card is as simple as calling `CreditCard#valid?`, which
 returns `true` only if the credentials are syntactically valid. If there are any errors or omissions,
-the `#errors` attribute will be non-empty.
+the `CreditCard#errors` attribute will be non-empty.