Explicit env vars

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This allows the process to use the .env file without any extra user steps needed.

The configuration in use is logged so it is clear what the expected environment vars will be:

16:55:21 bot.1      | 2014/07/10 16:55:21 START. Use 'botbot -help' for command line options.
16:55:21 bot.1      | 2014/07/10 16:55:21 Environment variables have been set from the .env file
16:55:21 bot.1      | 2014/07/10 16:55:21 STORAGE_URL:  postgres://localhost:5432/botbot
16:55:21 bot.1      | 2014/07/10 16:55:21 REDIS_PLUGIN_QUEUE_URL:  redis://localhost:6379/0