Adds back home/local/federated tabs

I don't think this is how I want the UI to work in the long run,
but for now it's better than not having it.
Fixes #210

bookwyrm/templates/feed.html

@@ -33,6 +33,20 @@
     </div>
 
     <div class="column is-two-thirds" id="feed">
+        <div class="tabs">
+            <ul>
+                <li class="{% if tab == 'home' %}is-active{% endif %}">
+                    <a href="/#feed">Home</a>
+                </li>
+                <li class="{% if tab == 'local' %}is-active{% endif %}">
+                    <a href="/local#feed">Local</a>
+                </li>
+                <li class="{% if tab == 'federated' %}is-active{% endif %}">
+                    <a href="/federated#feed">Federated</a>
+                </li>
+            </ul>
+        </div>
+
         {% if not activities %}
         <p>There aren't any activities right now! Try following a user to get started</p>
         {% endif %}

bookwyrm/urls.py

@@ -45,6 +45,7 @@ urlpatterns = [
     re_path(r'^invite/(?P<code>[A-Za-z0-9]+)/?$', views.invite_page),
 
     path('', views.home),
+    re_path(r'^(?P<tab>home|local|federated)/?$', views.home_tab),
     re_path(r'^notifications/?', views.notifications_page),
     re_path(r'import/?$', views.import_page),
     re_path(r'import_status/(\d+)/?$', views.import_status),

bookwyrm/views.py

@@ -44,6 +44,12 @@ def not_found_page(request, _):
 
 @login_required
 def home(request):
+    ''' this is the same as the feed on the home tab '''
+    return home_tab(request, 'home')
+
+
+@login_required
+def home_tab(request, tab):
     ''' user's homepage with activity feed '''
     # TODO: why on earth would this be where the pagination is set
     page_size = 15
@@ -81,7 +87,7 @@ def home(request):
         if len(suggested_books) >= count:
             break
 
-    activities = get_activity_feed(request.user, 'home')
+    activities = get_activity_feed(request.user, tab)
 
     activity_count = activities.count()
     activities = activities[(page - 1) * page_size:page * page_size]
@@ -94,6 +100,7 @@ def home(request):
         'activities': activities,
         'review_form': forms.ReviewForm(),
         'quotation_form': forms.QuotationForm(),
+        'tab': tab,
         'comment_form': forms.CommentForm(),
         'next': next_page if activity_count > (page_size * page) else None,
         'prev': prev_page if page > 1 else None,