made network migration repeatable

common/src/main/resources/migrations/loginLog/002_add_network.sql

@@ -1,6 +1,6 @@
 -- Connection key per attempt: the IPv4 address or the IPv6 /64 prefix. Groups accounts by internet connection.
 ALTER TABLE login_attempts
-    ADD COLUMN network VARCHAR(45) NULL COMMENT 'IPv4 address or IPv6 /64 prefix, NULL if unknown' AFTER ip,
-    ADD KEY idx_network_at (network, at);
+    ADD COLUMN IF NOT EXISTS network VARCHAR(45) NULL COMMENT 'IPv4 address or IPv6 /64 prefix, NULL if unknown' AFTER ip,
+    ADD KEY IF NOT EXISTS idx_network_at (network, at);
 
 UPDATE login_attempts SET network = ip WHERE ip REGEXP '^[0-9]{1,3}([.][0-9]{1,3}){3}$';