Who are Ramnamis, devotees of Lord Ram who have his name tattooed on their bodies?

The Ramnami Samaj emerged in the 19th century as a peaceful resistance movement against India's prevailing caste system. They have the name of Lord Ram tattooed on their faces and bodies in a symbolic act to convey that he's omnipresent. In a recent statement, the Ramnamis said their ancestors had predicted the Ram Lalla idol's consecration ceremony 150 years ago.