donation error handling

app/controllers/donations_controller.rb

@@ -1,10 +1,21 @@
 class DonationsController < ApplicationController
   def create
     @campaign = Campaign.current
+    begin
       @donation = Donation.create_from_charge(
         @campaign, current_user, params[:donation])
+    rescue Stripe::CardError => e
+      flash[:alert] = "We couldn't process your donation: #{e.message}"
+      redirect_to :donate
+    rescue => e
+      flash[:alert] =
+        "We couldn't process your donation: #{e.message} " +
+        "Please try again later!"
+      redirect_to :donate
+    else
       redirect_to @donation
     end
+  end
 
   def show
     @donation = Donation.from_param(params[:id])