Following are some online resource you can use to create different diagrams in the project

https://app.diagrams.net/
https://www.diagrameditor.com/
https://chrome.google.com/webstore/detail/sea-quail-database-diagra/elkpialiknkiaebieojbgnhindepnlkg?hl=en
http://ondras.zarovi.cz/sql/demo/
https://creately.com/lp/uml-diagram-tool/
http://creately.com/app/
https://www.lucidchart.com/pages/examples/uml_diagram_tool
http://www.gliffy.com/uses/uml-software/
http://yuml.me/edit/23db58a4
https://www.websequencediagrams.com/#