FEATURE: Add timezone to core user_options (#8380)

* Add timezone to user_options table

* Also migrate existing timezone values from UserCustomField,
  which is where the discourse-calendar plugin is storing them

* Allow user to change their core timezone from Profile

* Auto guess & set timezone on login & invite accept & signup

* Serialize user_options.timezone for group members. this is so discourse-group-timezones can access the core user timezone, as it is being removed in discourse-calendar.

* Annotate user_option with timezone

* Validate timezone values

spec/requests/invites_controller_spec.rb

@@ -290,6 +290,16 @@ describe InvitesController do
             expect(json["success"]).to eq(true)
             expect(json["redirect_to"]).to eq(topic.relative_url)
           end
+
+          context "if a timezone guess is provided" do
+            it "sets the timezone of the user in user_options" do
+              put "/invites/show/#{invite.invite_key}.json", params: { timezone: "Australia/Melbourne" }
+              expect(response.status).to eq(200)
+              invite.reload
+              user = User.find(invite.user_id)
+              expect(user.user_option.timezone).to eq("Australia/Melbourne")
+            end
+          end
         end
 
         context 'failure' do

spec/requests/session_controller_spec.rb

@@ -1048,6 +1048,16 @@ RSpec.describe SessionController do
           expect(user.user_auth_tokens.count).to eq(1)
           expect(UserAuthToken.hash_token(cookies[:_t])).to eq(user.user_auth_tokens.first.auth_token)
         end
+
+        context "when timezone param is provided" do
+          it "sets the user_option timezone for the user" do
+            post "/session.json", params: {
+              login: user.username, password: 'myawesomepassword', timezone: "Australia/Melbourne"
+            }
+            expect(response.status).to eq(200)
+            expect(user.reload.user_option.timezone).to eq("Australia/Melbourne")
+          end
+        end
       end
 
       context 'when user has 2-factor logins' do

spec/requests/users_controller_spec.rb

@@ -702,6 +702,22 @@ describe UsersController do
         post_user
         expect(User.find_by(username: @user.username).locale).to eq('fr')
       end
+
+      context "when timezone is provided as a guess on signup" do
+        let(:post_user_params) do
+          { name: @user.name,
+            username: @user.username,
+            password: "strongpassword",
+            email: @user.email,
+            timezone: "Australia/Brisbane" }
+        end
+
+        it "sets the timezone" do
+          post_user
+          expect(response.status).to eq(200)
+          expect(User.find_by(username: @user.username).user_option.timezone).to eq("Australia/Brisbane")
+        end
+      end
     end
 
     context 'when creating a non active user (unconfirmed email)' do