Persist the tsearch_extras extension across rebuilding of the database

We do this by creating a new zulip{_test}_base database that only has the zulip
schema and the tsearch_extras extension.  We then use that as a template when
creating zulip{_test}.

(imported from commit 8adb4b98410e4042a0187902e89c99561eac8c8f)

tools/do-destroy-rebuild-database

@@ -1,6 +1,9 @@
 #!/bin/sh -xe
 
-echo "DROP SCHEMA zulip CASCADE; CREATE SCHEMA zulip;" | python manage.py dbshell
+psql -h localhost postgres zulip <<EOF
+DROP DATABASE IF EXISTS zulip;
+CREATE DATABASE zulip TEMPLATE zulip_base;
+EOF
 
 python manage.py syncdb --noinput
 python manage.py migrate

tools/generate-fixtures

@@ -21,7 +21,11 @@ fi
 
 mkdir -p zerver/fixtures
 
-echo "DROP SCHEMA zulip CASCADE; CREATE SCHEMA zulip;" | python manage.py dbshell --settings=zproject.test_settings
+psql -h localhost postgres zulip_test <<EOF
+DROP DATABASE IF EXISTS zulip_test;
+CREATE DATABASE zulip_test TEMPLATE zulip_test_base;
+EOF
+
 python manage.py syncdb --noinput --settings=zproject.test_settings
 python manage.py migrate --settings=zproject.test_settings --all
 migration_status "zerver/fixtures/migration-status"

tools/postgres-init-db

@@ -24,6 +24,7 @@ else
     exit
 fi
 
+DBNAME_BASE=${DBNAME}_base
 
 $ROOT_POSTGRES $DEFAULT_DB << EOF
 CREATE USER $USERNAME WITH PASSWORD '$PASSWORD';
@@ -37,13 +38,21 @@ chmod go-rw ~/.pgpass
 
 psql -h localhost postgres $USERNAME <<EOF
 DROP DATABASE IF EXISTS $DBNAME;
-CREATE DATABASE $DBNAME;
+DROP DATABASE IF EXISTS $DBNAME_BASE;
+CREATE DATABASE $DBNAME_BASE
 EOF
 
-DEFAULT_DB=$DBNAME
+psql -h localhost $DBNAME_BASE $USERNAME <<EOF
+CREATE SCHEMA zulip;
+EOF
 
-$ROOT_POSTGRES $DEFAULT_DB << EOF
+$ROOT_POSTGRES $DBNAME_BASE << EOF
 DROP SCHEMA public CASCADE;
+CREATE EXTENSION tsearch_extras SCHEMA zulip;
+EOF
+
+psql -h localhost postgres $USERNAME <<EOF
+CREATE DATABASE $DBNAME TEMPLATE $DBNAME_BASE;
 EOF
 
 echo "Database created"