add test case
Merge branch 'master' of https://github.com/bug-tracker-dev/bug-tracker.git
Merge branch 'master' of https://github.com/bug-tracker-dev/bug-tracker.git
modify the annotation of these class
modify the annotation of these classes
add cache annotation and hibernate version column
add the loadById method 
add ehcache 
add cache test case 
add loadById testcase
add the cache configration
add the version column