change adapter for travis from mysql2 to sqlite3
Fixed popular stocks query

* By pull request #68, updated_at is added to 'group by'.
  This might cause wrong result on popular_stocks.each,
  so I've fixed group method arguments from a string to
  multiple string arguments.
fix rspec settings
add expectation for link click trainsition
Merge pull request #75 from lodge/stabilize_travis

多分だいぶ安定したはず