Allow Multiple Invites to Party (#8683)

* (server) Add parties array to store invites

* (server) Lint files

* Update joinGroup, rejectGroupInvite, _inviteByUUID, and remove clearPartyInvitation.js

* Update user schema: detailed 'invitations.parties' attributes

* Code improvement and do not let invite twice

* Check if the user is already invited earlier in the code

* Added message to invitation page, and show all invitations

* Added join party confirmation alert

* Small fixes

* Created test: allow inviting a user to 2 different parties

* Updated tests

* Update invitations.parties on more places

* Small adjustments

* Updates on invitations.party references

* Show all invitations when user is already in a party

* Fixed notifications counter

* Update both 'party' and 'parties' at _handleGroupInvitation

* Updated a test

* Fixed small mistake at _handleGroupInvitation

* More test update

* Update invitation.party when removing single invite and small adjust at view

website/server/models/user/schema.js

@@ -384,6 +384,24 @@ let schema = new Schema({
     party: {type: Schema.Types.Mixed, default: () => {
       return {};
     }},
+    parties: [{
+      id: {
+        type: String,
+        ref: 'Group',
+        required: true,
+        validate: [validator.isUUID, 'Invalid uuid.'],
+      },
+      name: {
+        type: String,
+        required: true,
+      },
+      inviter: {
+        type: String,
+        ref: 'User',
+        required: true,
+        validate: [validator.isUUID, 'Invalid uuid.'],
+      },
+    }],
   },
 
   guilds: [{type: String, ref: 'Group', validate: [validator.isUUID, 'Invalid uuid.']}],