Change object model and add crate Error type

Cargo.lock

@@ -61,6 +61,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.102"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -1959,6 +1965,7 @@ checksum = "1ffae5123b2d3fc086436f8834ae3ab053a283cfac8fe0a0b8eaae044768a4c4"
 name = "ynabmunger"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "chrono",
  "clap",
  "csv",
@@ -1966,6 +1973,7 @@ dependencies = [
  "reqwest",
  "serde",
  "serde_json",
+ "thiserror",
  "tokio",
 ]