major db refactors

Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+serde = { version = "1.0.219" }
 teloxide = { version = "0.17.0", features = ["macros", "ctrlc_handler"] }
 tokio = { version = "1.0", features = ["macros", "rt-multi-thread"] }
 sqlx = { version = "0.8.6", features = [
@@ -14,17 +15,17 @@ sqlx = { version = "0.8.6", features = [
     "rust_decimal",
 ] }
 rust_decimal = { version = "1.33" }
-chrono = { version = "0.4" }
+chrono = { version = "0.4", features = ["serde"] }
 log = "0.4"
 env_logger = "0.11.8"
 anyhow = "1.0"
 dotenvy = "0.15"
 lazy_static = "1.4"
-serde = "1.0.219"
 futures = "0.3.31"
 thiserror = "2.0.16"
 teloxide-core = "0.13.0"
 num = "0.4.3"
+itertools = "0.14.0"
 
 [dev-dependencies]
 rstest = "0.26.1"