Precised that email are optional

templates/user/register.html

@@ -14,7 +14,7 @@
    							{{ range (index $.FormErrors "username")}}
    							<p class="error-text">{{ . }}</p>
    							{{end}}
-					<input type="email" name="email" id="email" class="form-input up-input" placeholder="{{call $.T "email_address" }}" value="{{ .Email }}"> <br>
+					<input type="email" name="email" id="email" class="form-input up-input" placeholder="{{call $.T "email_address" }} ({{call $.T "optional"}})" value="{{ .Email }}"> <br>
    							{{ range (index $.FormErrors "email")}}
    							<p class="error-text">{{ . }}</p>
    							{{end}}

translations/en-us.all.json

@@ -1426,5 +1426,9 @@
   {
     "id": "old",
     "translation": "old"
+  },
+  {
+    "id": "optional",
+    "translation": "Optional"
   }
 ]