Support multiple networks about apiary HOT 1 OPEN

I'm going to mark this as a good first issue while providing my thoughts on how this could be implemented:

The easiest way to set this up is to run a worker per network. The only environment variables we would need to change are ETH_NETWORK (as described above) and ETH_NODE. Each worker would use the same database for simplicity in terms of accessing the data on the same front-end and via the same API. We could also decide to separate these aspects, i.e. have a separate database, API and front-end for each network.

Based on ETH_NETWORK some things need to change in the worker:

If we go with the first option (one database and API for all networks), then each document would need to have a network property populated with the value from ETH_NETWORK. If not, this step can be ignored.

Furthermore, there are exists some network-dependent configuration, namely the address for the different kits and the address of the ENS registry.

At first we could just have a file with different values for each of these sets of data much the same way that the Aragon client does it. However, I think a more nice solution long-term would be to have the worker load a configuration file (something like json) with these values. This would allow people to run Apiary for their own custom networks.

from apiary.