ip bans: add hit counter, deleted flag, new ban type.

* Make IP bans soft deletable.
* Add a hit counter to track how many times an IP ban has blocked someone.
* Add a last hit timestamp to track when the IP ban last blocked someone.
* Add a new type of IP ban, the signup ban. Signup bans restrict new
  signups from editing anything until they've verified their email
  address.

test/functional/ip_bans_controller_test.rb

@@ -21,6 +21,11 @@ class IpBansControllerTest < ActionDispatch::IntegrationTest
           assert_response :redirect
         end
       end
+
+      should "log a mod action" do
+        post_auth ip_bans_path, @admin, params: { ip_ban: { ip_addr: "1.2.3.4", reason: "xyz" }}
+        assert_equal("ip_ban_create", ModAction.last.category)
+      end
     end
 
     context "index action" do
@@ -37,12 +42,12 @@ class IpBansControllerTest < ActionDispatch::IntegrationTest
       end
     end
 
-    context "destroy action" do
-      should "destroy an ip ban" do
-        assert_difference("IpBan.count", -1) do
-          delete_auth ip_ban_path(@ip_ban), @admin, params: {:format => "js"}
-          assert_response :success
-        end
+    context "update action" do
+      should "mark an ip ban as deleted" do
+        put_auth ip_ban_path(@ip_ban), @admin, params: { ip_ban: { is_deleted: true }, format: "js" }
+        assert_response :success
+        assert_equal(true, @ip_ban.reload.is_deleted)
+        assert_equal("ip_ban_delete", ModAction.last.category)
       end
     end
   end