jira中issue的优先级及描述

jira是个bug跟踪管理系统，许多开源项目也使用它来进行bugtrac，如：jenkins。

用户可以把产品中的bug report到jira上，创建问题issue并进行跟踪。

issue的优先级（priority）和描述（description）如下：

Priority	Description
Blocker	Blocks development and/or testing work, production could not run.
Critical	Crashes, loss of data, severe memory leak.
Major	Major loss of function.
Minor	Minor loss of function, or other problem where easy workaround is present.
Trivial	Cosmetic problem like misspelt words or misaligned text.