little modification on the databases's links
little modification on the databases's links

OmicsDI/ddi-web-app,BD2K-DDI/ddi-web-app,ChrisShen93/ddi-web-app,OmicsDI/ddi-web-app,OmicsDI/ddi-web-app,ChrisShen93/ddi-web-app,BD2K-DDI/ddi-web-app