Bug Fixes

• Update rustlings version in Cargo.lock (1cc40bc9)
• arc1: index mod should equal thread count (b4062ef6)
• enums3: Update Message::ChangeColor to take a tuple. (#457) (4b6540c7)
• exercises: adding question mark to quiz2 (101072ab)
• generics3: clarify grade change (47f7672c)
• structs3: Small adjustment of variable name (114b54cb)
• using_as: Add test so that proper type is returned. (#512) (3286c5ec)

Features

• Added iterators1.rs exercise (9642f5a3)
• Add ability to run rustlings on repl.it (#471) (8f7b5bd0)
• Add gitpod support (#473) (4821a8be)
• Remind the user of the hint option (#425) (816b1f5e)
• Remind the user of the hint option (#425) (9f61db5d)
• cli: Added 'cls' command to 'watch' mode (#474) (4f2468e1)
• try_from_into: Add insufficient length test (#469) (523d18b8)