def create
      @comment = Comment.new(params.permit(:content))
      @comment.user = @user
      @comment.post = @post
      if @comment.save
        render json: @comment
      else
        render json: @comment.errors, status: 422
      end
    end
def create
      @comment = Comment.new(params.permit(:content))
      @comment.user = @user
      @comment.post = @post
      if @comment.save
        render json: @comment
      else
        render json: @comment.errors, status: 422
      end
    end
Creates new comment belonging to the post

 `POST /api/boards/:board_id/posts/:post_id/`