Add Blackfire.io support

[navarr]

In order to trigger Blackfire build, .env file must contain WARDEN_BLACKFIRE=1

The following env variables should be set for Blackfire:

• BLACKFIRE_CLIENT_ID
• BLACKFIRE_CLIENT_TOKEN
• BLACKFIRE_SERVER_ID
• BLACKFIRE_SERVER_TOKEN

[Shero-Inc]

+1 this would be perfect.

[davidalger]

Tested this locally by adding the following to a .env.blackfire file in my project root (since .env is committed to the repo in my test case):

export WARDEN_BLACKFIRE=1
export BLACKFIRE_CLIENT_ID=<my_id>
export BLACKFIRE_CLIENT_TOKEN=<my_token>
export BLACKFIRE_SERVER_ID=<my_id>
export BLACKFIRE_SERVER_TOKEN=<my_token>

Then ran source .env.blackfire followed by warden env up -d to configure the blackfire-agent and php-blackfire containers. Worked flawlessly. You rock!

Need to update the README with some information on Blackfire support and this will be ready to merge and include in the next published release version.