Add express and init server

[bonustrack]

Changes:

• Add express
• Set "start" script with express server
• Display current head

[Sekhmet]

I wonder if this would be useful, as busy-db would be used for syncing blocks and inserting data into database and won't serve as API (or would it be API as well?)

[bonustrack]

I don't know if the API has to use the same codebase than budy-db but we will need to serve an API and the database should be on same server for latency reasons so i figured out it wouln't mind to have it on same codebase.

[Sekhmet]

I would focus this tool on only syncing blocks to DB. API would be different tool, but it would connect to the same database.

[bonustrack]

What if we make the indexer and API into a single repo for make it easier for dev and test until it's ready for production @Sekhmet ?

[Sekhmet]

I would use single repo for this, but I don't think that running API and sync in the same app is good idea.

[feruzm]

You could use servers from same data center which would have lowest latency, that way db and api could be on separate machine but close to each other.