- state.message cannot be null

- state.variable_name removed
- state.prev_state added
- user.variables data type changed to text (due to unknown string size)
- added unique index on user.telegram_id
- wallet.min_co_signers cannot be null
- added wallet_request table definition
- a bit of change in constraint naming

db/mysql.sql

 create table app_state
 (
     id            int auto_increment,
-    message       varchar(200) null,
+    message       varchar(200) not null,
     menu          varchar(200) null,
-    variable_name varchar(100) not null,
+    prev_state    int default 0 not null,
     constraint app_state_pk
         primary key (id)
 );
@@ -11,36 +11,54 @@ create table app_state
 create unique index app_state_id_uindex
     on app_state (id);
 
-
-
 create table app_user
 (
     id          int auto_increment,
     telegram_id int           not null,
     state_id    int default 0 not null,
     nickname    varchar(100)  null,
-    variables   varchar(200)  null,
+    variables   text  null,
     constraint app_user_pk
-        primary key (id)
-    constraint app_state_app_wallet_id_fk
+        primary key (id),
+    constraint app_user_state_id_fk
         foreign key (state_id) references app_state (id)
 );
 
 create unique index app_user_id_uindex
     on app_user (id);
 
+create unique index app_user_telegram_id_uindex
+    on app_user (telegram_id);
+
 create table app_wallet
 (
     id             int auto_increment,
     max_co_signers int          not null,
-    min_co_signers int          null,
+    min_co_signers int          not null,
     name           varchar(100) null,
     initiator_id   int          not null,
     constraint app_wallet_pk
         primary key (id),
-    constraint app_wallet_app_user_id_fk
+    constraint app_wallet_user_id_fk
         foreign key (initiator_id) references app_user (id)
 );
 
 create unique index app_wallet_id_uindex
     on app_wallet (id);
+
+create table app_wallet_request
+(
+    id          int auto_increment,
+    token       varchar(64) not null,
+    wallet_id   int         not null,
+    constraint app_wallet_request_pk
+        primary key (id),
+    constraint app_wallet_request_wallet_id_fk
+        foreign key (wallet_id) references app_wallet (id)
+);
+
+create unique index app_wallet_request_id_uindex
+    on app_wallet_request (id);
+
+create unique index app_wallet_request_token_uindex
+    on app_wallet_request (token);