encapsulate active record methods onto models
refactor out some ar calls, restructure against conditionals
extract omniauth concern from user
further remove omniauth from user
further remove concerns from user
remove has_completed? from user model
less bad name for Completion#user_completion
generalize render_bad_response
factor out ExerciseBlock
perf fixes for module show, fix rubocop complaints
fix view test, remove unused param
tighten up exercise_block_for
remove useless outputting from exercise questions
Merge pull request #41 from jmmastey/refactors

Basic refactoring, plus a performance change or two.