Add good bit of functionality, some tests

Signed-off-by: Vartan Benohanian <vartanbeno@gmail.com>

link.go

@@ -0,0 +1,72 @@
+package geddit
+
+import (
+	"context"
+	"errors"
+	"net/url"
+	"strings"
+)
+
+// LinkService handles communication with the link (post)
+// related methods of the Reddit API
+type LinkService interface {
+	Hide(ctx context.Context, ids ...string) (*Response, error)
+	Unhide(ctx context.Context, ids ...string) (*Response, error)
+}
+
+// LinkServiceOp implements the Vote interface
+type LinkServiceOp struct {
+	client *Client
+}
+
+var _ LinkService = &LinkServiceOp{}
+
+// Hide hides links with the specified ids
+// On successful calls, it just returns {}
+func (s *LinkServiceOp) Hide(ctx context.Context, ids ...string) (*Response, error) {
+	if len(ids) == 0 {
+		return nil, errors.New("must provide at least 1 id")
+	}
+
+	path := "api/hide"
+
+	form := url.Values{}
+	form.Set("id", strings.Join(ids, ","))
+
+	req, err := s.client.NewPostForm(path, form)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := s.client.Do(ctx, req, nil)
+	if err != nil {
+		return resp, err
+	}
+
+	return resp, nil
+}
+
+// Unhide unhides links with the specified ids
+// On successful calls, it just returns {}
+func (s *LinkServiceOp) Unhide(ctx context.Context, ids ...string) (*Response, error) {
+	if len(ids) == 0 {
+		return nil, errors.New("must provide at least 1 id")
+	}
+
+	path := "api/unhide"
+
+	form := url.Values{}
+	form.Set("id", strings.Join(ids, ","))
+
+	req, err := s.client.NewPostForm(path, form)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := s.client.Do(ctx, req, nil)
+	if err != nil {
+		return resp, err
+	}
+
+	return resp, nil
+}