unneeded use class
Merge pull request #4841 from tebazil/patch-1

[ci skip] unneeded use Model
fixed boolean handling for PostgreSQL

- do not allow boolean values for integer columns
- use native boolean type with boolean values
- removed workaround that turned out to be wrong when schema and values
  are used correctly. Workaround resulted from wrong usage of boolean
  values before.

fixes #4672
check if sphinx is installed
install cubrid DB not using sudo and use travis cache
try mongodb without sudo
fixed sphinx setup
sphinx setup without sudo
fixed cubrid PDO
enable mongo text search
simplified travis installation
Merge pull request #4848 from yiisoft/fix-travis

 try using the new Docker setup of travis-ci