ADD get readme api

app/controllers/repositories_controller.rb

@@ -133,6 +133,13 @@ class RepositoriesController < ApplicationController
     render_ok
   end
 
+  def readme
+    result = Gitea::Repository::Readme::GetService.call(@owner.login, @repository.identifier, params[:ref], current_user&.gitea_token)
+
+    @readme = result[:status] === :success ? result[:body] : nil
+    render json: @readme
+  end
+
   private
 
   def find_project

app/services/gitea/repository/readme/get_service.rb

@@ -0,0 +1,39 @@
+# Gets the preferred README for a repository.
+class Gitea::Repository::Readme::GetService < Gitea::ClientService
+  attr_reader :owner, :repo, :ref, :token
+
+  # owner: owner of the repo
+  # repo: name of the repo
+  # name: The name of the commit/branch/tag. Default: the repository’s default branch (usually master)
+  # eg:
+  # Gitea::Repository::Readme::GetService.call(user.login, repo.identifier, ref, user.gitea_token)
+  def initialize(owner, repo, ref, token=nil)
+    @owner = owner
+    @repo  = repo
+    @ref   = ref || 'master'
+    @token = token
+  end
+
+  def call
+    response = get(url, params)
+    status, message, body = render_response(response)
+    json_format(status, message, body)
+  end
+
+  private
+  def params
+    Hash.new.merge(token: token, ref: ref)
+  end
+
+  def url
+    "/repos/#{owner}/#{repo}/readme".freeze
+  end
+
+  def json_format(status, message, body)
+    case status
+    when 200 then success(body)
+    when 404 then error(message, 404)
+    else error(message, status)
+    end
+  end
+end