This commit is working on issue #1, #2,  #3, #4.
 - closed #1
 - #2 : in progress. sql insert message has been designed. Primary key is auto-incremental, and the sql execution automatically records its time of creation.
 - #3 : Articles are printed in descending order, 10 maximum row, latest on top.
 - #4 : in progress. sql update message has been designed. It records modified time automatically.