Fix incorrect description in 07_joins_exercises spec.
Clarify instructions in area_count.
Fix spec and solution for films_by_cast_size
Move README.md to skeleton/solution folders
area in 1000's of sq. km.
update Gemfile.lock (no byebug)
add literature_1962 example
simplify solution to large_neighbors
"at least" means >=
fix spec to reflect 5a60294
specify formerly ambiguous movie ordering
clarify LEFT OUTER JOIN prompt
Fix typos in 08_using_null.rb
Finished Lessons, Fixed Rspec