add a quick note about error handling to the README [ci-skip]

Author: Erik DeBill

README.md

@@ -158,6 +158,26 @@ end
 # => 1
 ```
 
+## Error Handling
+
+In general, if something goes wrong you'll get an exception. For example, if
+it can't connect to the server a `Redis::CannotConnectError` error will be raised.
+
+```ruby
+begin
+  redis.ping
+rescue Exception => e
+  e.inspect
+# => #<Redis::CannotConnectError: Timed out connecting to Redis on 10.0.1.1:6380>
+
+  e.message
+# => Timed out connecting to Redis on 10.0.1.1:6380
+end
+```
+
+See lib/redis/errors.rb for information about what exceptions are possible.
+
+
 ## Expert-Mode Options
 
  - `inherit_socket: true`: disable safety check that prevents a forked child