Remove redundant postcode validation

[mbarton]

/validate does the same underlying database lookup at their end as the normal API so we don't need the additional call. This makes the API about twice as fast.

Before

time curl 'http://localhost:8001/index_of_multiple_deprivation_quantile?postcode=W1A1AA&quantile=5'
{"result":{"rank":15472,"requested_quantile":5,"requested_quantile_name":"quintile","data_quantile":3,"country":"england","error":null}}
real    0m0.186s
user    0m0.002s
sys     0m0.003s

After

time curl 'http://localhost:8001/index_of_multiple_deprivation_quantile?postcode=W1A1AA&quantile=5'
{"result":{"rank":15472,"requested_quantile":5,"requested_quantile_name":"quintile","data_quantile":3,"country":"england","error":null}}
real    0m0.103s
user    0m0.002s
sys     0m0.003s

[pacharanero]

I can't see any difference between Before and After in the first post...

[mbarton]

Whoops, have updated with the correct timings

[pacharanero]

Aha yes much faster

[anchit-chandran]

this is a fantastically simple improvement, really good catch! LGTM