chore: updated README; added service example file

chore: added Postman collection and environment

chore: updated README

chore: created dislike post method

chore: created like post method

chore: created post delete and 'search by user' methods

chore: created post update method

chore: created post search method

chore: created post 'search by id' method

chore: created post validation methods

chore: created post create method

chore: created post model

fix: user model 'Prepare' typo

chore: created change password method

chore: created following search method