Add statics and methods to models

@@ -8,5 +8,10 @@ const GroupSchema = new Schema({
     collection: 'group'
 });
 
+GroupSchema.methods.addGroupMemeber=function(user){
+    this.members.push({$oid:user._id.$oid});
+    return this.save();
+}
+
 const Group = mongoose.model('Group',GroupSchema);
 module.exports = Group;
\ No newline at end of file

@@ -2,12 +2,32 @@ const mongoose = require("mongoose");
 
 const { Schema } = mongoose;
 
+const SelectedProblemSchema=new Schema({
+    problemNum: {type: Number, required: true},
+    isSolved: {type:Boolean, default: false},
+},{
+    _id: false
+});
+
 const ParticipationSchema = new Schema({
     sessionId: { type: Schema.Types.ObjectId, ref: 'Session' },
-    groupId: { type: Schema.Types.ObjectId, ref: 'Group' }
+    groupId: { type: Schema.Types.ObjectId, ref: 'Group' },
+    problems: [{type:SelectedProblemSchema}]
 },{
     collection: 'particiaption'
 });
 
+ParticipationSchema.statics.findBySessionId=function(session){
+    return this.find({sessionId:session._id.$oid});
+}
+
+ParticipationSchema.statics.findByGroupId=function(group){
+    return this.find({groupId:group._id.$oid});
+}
+
+ParticipationSchema.methods.addProblem=function(problem){
+    this.problems.push({problemNum:problem.problemNum,isSolved:problem.isSolved});
+}
+
 const Participation = mongoose.model('Participation', ParticipationSchema);
 module.exports = Participation;
\ No newline at end of file

@@ -11,5 +11,25 @@ const SessionSchema = new Schema({
     collection: 'session'
 });
 
+SessionSchema.statics.findByChallengeId=function(challenge){
+    return this.find({challengeId:challenge._id.$oid});
+}
+
+SessionSchema.methods.getSessionStartDate=function(){
+    return this.sessionStartDate;
+}
+
+SessionSchema.methods.getSessionEndDate=function(){
+    return this.sessionEndDate;
+}
+
+SessionSchema.methods.getIsOpen=function(){
+    return this.isOpen;
+}
+
+SessionSchema.methods.serialize=function(){
+    return this.toJSON();
+}
+
 const Session = mongoose.model('Session', SessionSchema);
 module.exports = Session;
\ No newline at end of file

@@ -21,6 +21,11 @@ UserSchema.statics.findByUsername = function (username) {
   return this.findOne({ username });
 };
 
+UserSchema.methods.addFriend=function(friend){
+  this.friendList.push({$oid:friend._id.$oid});
+  return this.save();
+}
+
 UserSchema.methods.setPassword = async function (password) {
   const hash = await bcrypt.hash(password, 10);
   this.hashedPassword = hash;