Display OAuth login on login form button.

src/components/login_form/login_form.vue

@@ -26,7 +26,7 @@
         <div class='form-group'>
           <div class='login-bottom'>
             <div><router-link :to="{name: 'registration'}" v-if='registrationOpen' class='register'>{{$t('login.register')}}</router-link></div>
-            <button :disabled="loggingIn" type='submit' class='btn btn-default'>{{$t('login.login')}}</button>
+            <button :disabled="loggingIn" type='submit' class='btn btn-default'>{{$t('login.login_token')}}</button>
           </div>
         </div>
       </form>

src/i18n/de.json

@@ -12,6 +12,7 @@
   },
   "login": {
     "login": "Anmelden",
+    "login_token": "Mit OAuth anmelden",
     "logout": "Abmelden",
     "password": "Passwort",
     "placeholder": "z.B. lain",

src/i18n/en.json

@@ -21,6 +21,7 @@
   },
   "login": {
     "login": "Log in",
+    "login_token": "Log in with OAuth",
     "logout": "Log out",
     "password": "Password",
     "placeholder": "e.g. lain",