added a static method to clear a user's redis keys
added a static method to clear a user's redis keys

tndatacommons/tndata_backend,izzyalonso/tndata_backend,izzyalonso/tndata_backend,tndatacommons/tndata_backend,tndatacommons/tndata_backend,izzyalonso/tndata_backend,tndatacommons/tndata_backend,izzyalonso/tndata_backend