SCB-344 add document for how to use mysql as alpha's backend database

[eric-lee-ltk]

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This PR is based on #135 .

As the default table name in eclipselink is upper case and table name in query is case sensitive, we need to explicitly tell the query the exact table name. That's why the @Table came for.

[coveralls]

Coverage remained the same at 95.273% when pulling d124955 on eric-lee-ltk:SCB-344 into 697bf60 on apache:master.