Added session creating

server/migrations/003_create_sessions.sql

@@ -0,0 +1,7 @@
+CREATE TABLE "sessions" (
+    session_id  uuid      NOT NULL PRIMARY KEY,
+    user_id     uuid      NOT NULL REFERENCES users (user_id) ON UPDATE cascade ON DELETE cascade,
+    token       text      NOT NULL UNIQUE,
+    expires_at  timestamptz  NOT NULL, 
+    created_at  timestamptz  NOT NULL
+);