add db example
add db example

sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc