Allow public dashboards

Dashboards can now be marked as publically visible in the user
preferences. The dashboard URL has changed from /user/<name>/dashboard
to /dashboard/<name> because /user/<name> requires being logged in as
<name> or as an admin.

src/sql/hydra.sql

@@ -10,7 +10,8 @@ create table Users (
     emailAddress  text not null,
     password      text not null, -- sha256 hash
     emailOnError  integer not null default 0,
-    type          text not null default 'hydra' -- either "hydra" or "persona"
+    type          text not null default 'hydra', -- either "hydra" or "persona"
+    publicDashboard boolean not null default false
 );