problems.md in trackler-2.0.0.2

- old
+ new

@@ -21,10 +21,11 @@
 leap |  math, booleans, conditionals
 raindrops |  case (or `format`). Mutable string
 bob |  chars, string functions
 beer-song |  case, string concatenation, vector (optional), loop
 difference-of-squares |  fold & map
+grains | math, panic
 
 ## Getting Rusty
 
 Problems begin to use more Rust-specific features. Try to only introduce one new language feature at a time. And if several problems rely on a feature, try to group them so as to reinforce its usage.
 
@@ -46,9 +47,10 @@
 all-your-base |  Result, enumerate, fold, map
 grade-school |  struct, entry api, Vec, Option
 robot-simulator | Immutability, enum
 bracket-push | From trait, stack or recursion
 queen-attack |  struct, trait (optional), Result
+bowling | struct, Result, goofy bowling logic
 sublist |  enum, generic over type
 space-age | Custom Trait, From Trait, Default Trait implementation
 allergies |  struct, enum, bitwise (probably), vectors, filter
 variable-length-quantity | Encodings, slices, bitwise, Result
 phone-number |  option, format, unwrap_or, iters, match