Esajas has been on trial at the club over the last few weeks and impressed manager Brian Laws enough to earn himself a full contract.
"I am delighted to have signed," he told the Official Website.
"It has been hard work for me, but I am happy so far and pleased to be here.
"The squad is full of lovely guys. When I first came in they took care of me and supported me, and I can tell you it's never easy for a trialist but they have been great here.
"We need to push for promotion".