database: Add search tables

Signed-off-by: Eduardo L. Buratti <elb09@c3sl.ufpr.br>

database/create/005-search.sql

+-- search tables
+CREATE TABLE search_school (
+    id              SERIAL PRIMARY KEY,
+    sch_id          INTEGER NOT NULL REFERENCES dim_school,
+    cit_id          INTEGER NOT NULL REFERENCES dim_city,
+
+    ts_vector       TSVECTOR,
+    contacted_once  BOOLEAN NOT NULL DEFAULT false
+);