Set time zone on login

Should be more reliable.

vedia.rb

@@ -133,6 +133,7 @@ post '/login' do
     end
     session.clear
     session[:user_id] = user.id
+    session[:timezone] = params[:timezone]
     redirect '/'
   else
     @error = _("Incorrect email or password.")
@@ -140,10 +141,6 @@ post '/login' do
   end
 end
 
-post '/timezone' do
-  session[:timezone] = JSON.parse(request.body.read)['timezone']
-end
-
 get '/reset' do
   erb :reset
 end
@@ -641,12 +638,7 @@ helpers do
   end
 
   def format_date(timestamp)
-    if session[:timezone]
-      "#{TZInfo::Timezone.get(session[:timezone]).to_local(timestamp).strftime('%F')}"
-    else
-      # Otherwise, format_date fails on first page after login. Not sure why...
-      "#{timestamp.strftime('%F')}"
-    end
+    "#{TZInfo::Timezone.get(session[:timezone]).to_local(timestamp).strftime('%F')}"
   end
 
   def format_date_and_time(timestamp)