move to postgres; implement marking caught fish

migrations/20250206105906_initial.sql

@@ -1,10 +1,12 @@
 -- Add migration script here
-CREATE TABLE accounts (account_id VARCHAR(10) PRIMARY KEY);
+CREATE TABLE accounts (
+    account_id VARCHAR(10) PRIMARY KEY NOT NULL UNIQUE
+);
 
 CREATE TABLE caught_fish (
-    id INTEGER PRIMARY KEY,
-    account_id VARCHAR(10),
-    fish_id INTEGER,
+    id SERIAL PRIMARY KEY,
+    account_id VARCHAR(10) NOT NULL,
+    fish_id INTEGER NOT NULL,
     FOREIGN KEY (account_id) REFERENCES accounts (account_id) ON DELETE CASCADE ON UPDATE NO ACTION
 );