diff --git a/oauth_slack.go b/oauth_slack.go
index 8cf4992..f700c2c 100644
--- a/oauth_slack.go
+++ b/oauth_slack.go
@@ -1,170 +1,170 @@
 package writefreely
 
 import (
 	"context"
 	"errors"
 	"fmt"
 	"github.com/writeas/nerds/store"
 	"github.com/writeas/slug"
 	"net/http"
 	"net/url"
 	"strings"
 )
 
 type slackOauthClient struct {
 	ClientID         string
 	ClientSecret     string
 	TeamID           string
 	CallbackLocation string
 	HttpClient       HttpClient
 }
 
 type slackExchangeResponse struct {
 	OK          bool   `json:"ok"`
 	AccessToken string `json:"access_token"`
 	Scope       string `json:"scope"`
 	TeamName    string `json:"team_name"`
 	TeamID      string `json:"team_id"`
 	Error       string `json:"error"`
 }
 
 type slackIdentity struct {
 	Name  string `json:"name"`
 	ID    string `json:"id"`
 	Email string `json:"email"`
 }
 
 type slackTeam struct {
 	Name string `json:"name"`
 	ID   string `json:"id"`
 }
 
 type slackUserIdentityResponse struct {
 	OK    bool          `json:"ok"`
 	User  slackIdentity `json:"user"`
 	Team  slackTeam     `json:"team"`
 	Error string        `json:"error"`
 }
 
 const (
 	slackAuthLocation     = "https://slack.com/oauth/authorize"
 	slackExchangeLocation = "https://slack.com/api/oauth.access"
 	slackIdentityLocation = "https://slack.com/api/users.identity"
 )
 
 var _ oauthClient = slackOauthClient{}
 
 func (c slackOauthClient) GetProvider() string {
 	return "slack"
 }
 
 func (c slackOauthClient) GetClientID() string {
 	return c.ClientID
 }
 
 func (c slackOauthClient) GetCallbackLocation() string {
 	return c.CallbackLocation
 }
 
 func (c slackOauthClient) buildLoginURL(state string) (string, error) {
 	u, err := url.Parse(slackAuthLocation)
 	if err != nil {
 		return "", err
 	}
 	q := u.Query()
 	q.Set("client_id", c.ClientID)
 	q.Set("scope", "identity.basic identity.email identity.team")
 	q.Set("redirect_uri", c.CallbackLocation)
 	q.Set("state", state)
 
 	// If this param is not set, the user can select which team they
 	// authenticate through and then we'd have to match the configured team
 	// against the profile get. That is extra work in the post-auth phase
 	// that we don't want to do.
 	q.Set("team", c.TeamID)
 
 	// The Slack OAuth docs don't explicitly list this one, but it is part of
 	// the spec, so we include it anyway.
 	q.Set("response_type", "code")
 	u.RawQuery = q.Encode()
 	return u.String(), nil
 }
 
 func (c slackOauthClient) exchangeOauthCode(ctx context.Context, code string) (*TokenResponse, error) {
 	form := url.Values{}
 	// The oauth.access documentation doesn't explicitly mention this
 	// parameter, but it is part of the spec, so we include it anyway.
 	// https://api.slack.com/methods/oauth.access
 	form.Add("grant_type", "authorization_code")
 	form.Add("redirect_uri", c.CallbackLocation)
 	form.Add("code", code)
 	req, err := http.NewRequest("POST", slackExchangeLocation, strings.NewReader(form.Encode()))
 	if err != nil {
 		return nil, err
 	}
 	req.WithContext(ctx)
 	req.Header.Set("User-Agent", "writefreely")
 	req.Header.Set("Accept", "application/json")
 	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 	req.SetBasicAuth(c.ClientID, c.ClientSecret)
 
 	resp, err := c.HttpClient.Do(req)
 	if err != nil {
 		return nil, err
 	}
 	if resp.StatusCode != http.StatusOK {
 		return nil, errors.New("unable to exchange code for access token")
 	}
 
 	var tokenResponse slackExchangeResponse
 	if err := limitedJsonUnmarshal(resp.Body, tokenRequestMaxLen, &tokenResponse); err != nil {
 		return nil, err
 	}
 	if !tokenResponse.OK {
 		return nil, errors.New(tokenResponse.Error)
 	}
 	return tokenResponse.TokenResponse(), nil
 }
 
 func (c slackOauthClient) inspectOauthAccessToken(ctx context.Context, accessToken string) (*InspectResponse, error) {
 	req, err := http.NewRequest("GET", slackIdentityLocation, nil)
 	if err != nil {
 		return nil, err
 	}
 	req.WithContext(ctx)
 	req.Header.Set("User-Agent", "writefreely")
 	req.Header.Set("Accept", "application/json")
 	req.Header.Set("Authorization", "Bearer "+accessToken)
 
 	resp, err := c.HttpClient.Do(req)
 	if err != nil {
 		return nil, err
 	}
 	if resp.StatusCode != http.StatusOK {
 		return nil, errors.New("unable to inspect access token")
 	}
 
 	var inspectResponse slackUserIdentityResponse
 	if err := limitedJsonUnmarshal(resp.Body, infoRequestMaxLen, &inspectResponse); err != nil {
 		return nil, err
 	}
 	if !inspectResponse.OK {
 		return nil, errors.New(inspectResponse.Error)
 	}
 	return inspectResponse.InspectResponse(), nil
 }
 
 func (resp slackUserIdentityResponse) InspectResponse() *InspectResponse {
 	return &InspectResponse{
 		UserID:      resp.User.ID,
-		Username:    fmt.Sprintf("%s-%s", slug.Make(resp.User.Name), store.Generate62RandomString(5)),
+		Username:    fmt.Sprintf("%s-%s", slug.Make(resp.User.Name), store.GenerateRandomString("0123456789bcdfghjklmnpqrstvwxyz", 5)),
 		DisplayName: resp.User.Name,
 		Email:       resp.User.Email,
 	}
 }
 
 func (resp slackExchangeResponse) TokenResponse() *TokenResponse {
 	return &TokenResponse{
 		AccessToken: resp.AccessToken,
 	}
 }