Backblaze, db bugfixes and connection testing.

src/db-init.sql

@@ -10,7 +10,10 @@ create unique index users_auth_user_id_idx on users (auth_user_id);
 
 create table instances(
        instance_id bigserial primary key,
-       user_id integer not null references users on delete cascade
+       user_id integer not null references users on delete cascade,
+       ssh_key_priv_enc text,
+       ssh_key_pub_enc text,
+       restic_password_enc varchar(255)
 );
 create unique index instances_user_id_instance_id_idx on instances (instance_id, user_id);