Hello you can modifi the educat homepage in developpmode.Login as admin >about>technical user>Userinterface>view,  goto the search field and hit backspace>then type: homepage. Now you see Qweb -- website.homepage, you can edit.

Extremely sorry I  don't have enough karma that's why I am posting as an answer.

I am using openeducat modules and I want to use them further. So is there any other way I can redirect my site to login page instead of website

You could solve it by deleting the openeducat views or altering the content to not do anything. This could be do it using an xml loaded in an installed module or manually on your Odoo UI. If your website was installed using a custom module that install the design you could put a dependency with openeducat so your module will be loaded after openeducat module and you could change or remove the openeducat views from your module.

Hello @nitin

You just change in openeducate core module 

homepage_template.xml file