How to choose feed producers

We need to setup standards for feed producers.
We need to define a workflow about how to choose feed producers and how to pay them.

As [proposed in the forum](https://bitsharestalk.org/index.php?topic=29690.0), my initial idea:
* feed producers deposit some BTS to committee or another account controlled by the community
* the community define the rules / formulas for feeding price. Feed producers are encouraged to participate in the process
* the community allows some feed producers to experiment new rules
* feed producers will get paid according to their performance, will get paid less if not done the job good enough
* the deposit will be deducted if a feed producer made serious mistakes.

Still need to work out the details.

Please discuss.