Show existing artists on the registration page (#95)

Try to avoid artists accidentally creating multiple profiles if they
don't intend to.

artshow/register.py

@@ -38,6 +38,8 @@ def main(request):
         artist_form = ArtistRegisterForm()
         agreement_form = AgreementForm()
 
+    artists = Artist.objects.viewable_by(request.user)
     return render(request, "artshow/manage_register_main.html",
-                  {"artist_form": artist_form,
+                  {"artists": artists,
+                   "artist_form": artist_form,
                    "agreement_form": agreement_form})

artshow/templates/artshow/manage_register_main.html

@@ -1,11 +1,37 @@
 {% extends "artshow/manage_base.html" %}
 {% block content %}
 <p>
-    Welcome to the Art Show! To register for space in the show, please fill in
-    the following information.
+    Welcome to the Art Show! Most of your details have been copied from your
+    convention registration.
+</p>
+
+{% if artists %}
+<p>You have already registered the following artist profiles:</p>
+<table>
+    <tr>
+        <th>Artist Name</th>
+        <th>Artist ID</th>
+        <th>Pieces Entered</th>
+    </tr>
+    {% for artist in artists %}
+    <tr>
+        <td><a href="{% url 'artshow-manage-artist' artist.pk %}">{{ artist.artistname }}</a></td>
+        <td>{{ artist.artistid }}</td>
+        <td>{{ artist.piece_set.count }}</td>
+    </tr>
+    {% endfor %}
+</table>
+
+<p>
+    If you would like you create a separate artist profile to enter pieces under
+    a different public name, please fill in the form below:
+</p>
+{% else %}
+<p>
+    To register for the show, please fill in the following information to create
+    an artist profile:
 <p>
-<p>Once there, you'll be able to request space in the show, provide payment for the space, enter piece
-    details, and so on.</p>
+{% endif %}
 
 <form method="post">{% csrf_token %}
     <table>