func (s *ActivityService) GetRepositorySubscription(ctx context.Context, owner, repo string) (*Subscription, *Response, error) {
	u := fmt.Sprintf("repos/%s/%s/subscription", owner, repo)
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	sub := new(Subscription)
	resp, err := s.client.Do(ctx, req, sub)
	if err != nil {
		_, err = parseBoolResponse(err)
		return nil, resp, err
	}
	return sub, resp, nil
}
GetRepositorySubscription returns the subscription for the specified
repository for the authenticated user. If the authenticated user is not
watching the repository, a nil Subscription is returned.

GitHub API docs: https://developer.github.com/v3/activity/watching/#get-a-repository-subscription
package github
import (
	"context"
	"fmt"
)
type Subscription struct {
	Subscribed *bool      `json:"subscribed,omitempty"`
	Ignored    *bool      `json:"ignored,omitempty"`
	Reason     *string    `json:"reason,omitempty"`
	CreatedAt  *Timestamp `json:"created_at,omitempty"`
	URL        *string    `json:"url,omitempty"`
	RepositoryURL *string `json:"repository_url,omitempty"`
	ThreadURL *string `json:"thread_url,omitempty"`
}
func (s *ActivityService) ListWatchers(ctx context.Context, owner, repo string, opt *ListOptions) ([]*User, *Response, error) {
	u := fmt.Sprintf("repos/%s/%s/subscribers", owner, repo)
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	var watchers []*User
	resp, err := s.client.Do(ctx, req, &watchers)
	if err != nil {
		return nil, resp, err
	}
	return watchers, resp, nil
}
func (s *ActivityService) ListWatched(ctx context.Context, user string, opt *ListOptions) ([]*Repository, *Response, error) {
	var u string
	if user != "" {
		u = fmt.Sprintf("users/%v/subscriptions", user)
	} else {
		u = "user/subscriptions"
	}
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	var watched []*Repository
	resp, err := s.client.Do(ctx, req, &watched)
	if err != nil {
		return nil, resp, err
	}
	return watched, resp, nil
}