Future-proof schema, to support other transport companies and cities

[roata]

The current data structures are tied to RTEC. What we need is to make it future-proof and extendable, such that we can cover other transport networks in Chișinău (PUA - parcul urban de autobuze and the minibuses) and other cities.

The new schema must:

1. Be backwards compatible
2. Accommodate other cities
3. Accommodate other transport networks within the same city
4. Maybe, be modularized - such that one could get and cache just the data they want, instead of downloading lots of unnecessary data

At the moment I am still inclined to use CSV files, but alternatives will be considered. The current proposal is to:

1. Add 2 more columns to each routes.csv and vehicles.csv file: city_id, network_id
2. Add 2 more CSV files: cities.csv, where Chișinău=1 :-) and transport-networks.csv, where RTEC=1
3. Potentially, we could have several scripts that generate city-specific files, so the folks in other parts of Moldova could rely on those reduced data-sets, which will make their downloads a bit faster.

@iamandrewluca @PlugaruT, what do you think?

I would like to work on this during the weekend, so it would be great if you could share your thoughts until then.

[iamandrewluca]

I agree with your proposal.

As a reference, map.md keeps their routes in this format

CREATE TABLE routes (
    id integer,
    type integer, # 0, 1, 2 (bus, minibus, trolleybus)
    city_id integer,
    number text,
)

id	type	city_id	number
338	2	265099165	"10"

CREATE TABLE locations (
    id integer,
    name text,
    lat real,
    lon real,
    is_in text,
)

id	name	lat	lon	is_in
277625074	"Costești"	46.86725	28.7679943	"Ialoveni"