Replace all "numeric" with "float8"

script/sql/create/4.tanks.sql

@@ -5,12 +5,12 @@ create type tanks_overflow as enum ('YES', 'NO');
 create table tanks
 (
   id varchar(32) primary key references _node(id)
-, elevation numeric not null
-, init_level numeric not null
-, min_level numeric not null
-, max_level numeric not null
-, diameter numeric not null
-, min_vol numeric not null
+, elevation float8 not null
+, init_level float8 not null
+, min_level float8 not null
+, max_level float8 not null
+, diameter float8 not null
+, min_vol float8 not null
 , vol_curve varchar(32) references _curve(id)
 , overflow tanks_overflow
 );