And run `npm install` to generate `package-lock.json`.

This is where I'll add custom code to define the AWS resources which
make up the stack.

This rule currently has no target and so won't do anything, but it's a
small step on the way.

Note that Ruby lambda functions cannot currently be "inline"; they have
to be in a separate file.

Note this is closely based on the original instructions [1].

[1]: https://github.com/freerange/trello_backup/blob/a99bacf2f663c899a76947dd91810c6ee353d429/README.md#generatingstoring-the-tokens-you-need-to-use-this-script

Note that unfortunately the trello gem currently (rather unnecessarily)
has an indirect dependency on the unf gem which has native extensions.
When I was trying this previously, I thought I ran into problems because
the extensions were being built on my local machine using Mac OSX
(x86_64-darwin-17), but were being deployed and run in an AWS Lambda
function which is an x86_64-linux platform. Previously I had used Docker
to build the extensions for the correct platform, however, when I just
tried deploying and running the function as it stands (with Mac
OSX-build extensions), it seemed to work OK, so maybe the whole Docker
thing was unnecessary!

I've chosen to use the board ID rather than a normalized version of the
board name for the S3 object key, because this is a lot less likely to
change over time.

There's no need to include a timestamp in the S3 object key, because the
S3 bucket has versioning enabled.

I've confirmed that even a single exception from one of the lambda
functions will trigger an alarm email notification.

This means all the env vars are obtained at the same level.

To minimize the size of the zip file uploaded to AWS.

And reduce the size of the zip file uploaded to AWS.

And reduce the size of the zip file uploaded to AWS.

I noticed this was missing when I was comparing this project with the
`trello-full-backup` Python package [1].

[1]: https://pypi.org/project/trello-full-backup/

Move key & token to beginning of list and order the remaining keys
alphabetically.

This should hopefully speed up the API response time.

To make its purpose clearer.

I'm planning to use this topic for monitoring as well as alarms.

No need to include "Trello" in constant name.

No need to repeat "Trello" in constant/function name.

No need to repeat "Trello" in constant/function name.

No need to repeat "Trello" in constant/function name.

TRELLO_BOARD_BACKUPS -> TRELLO_BACKUP.

BACKUP_TRELLO_BOARD_TOPIC_ARN -> TRELLO_BACKUP_BACKUP_BOARD_TOPIC_ARN.

This makes the code more consistent.

I want to introduce another schedule expression and this change which
makes the name more specific will make that easier.

Again this will make it easier to add another schedule expression rule.

Sends an email indicating whether the backup of all boards was
successful or not.