add possibility to send emails when user is added to a project

app/user/controller.py

@@ -10,7 +10,7 @@
 from .interface import UserInterface
 from .model import User
 from .schema import UserSchema
-from .service import UserService
+from .service import UserService, EmailService
 
 api = Namespace("User", description="Single namespace, single entity")  # noqa
 
@@ -68,3 +68,15 @@ def get(self):
         logout_user()
         js = json.dumps({"logout": True}, default=str)
         return Response(js, status=200, mimetype="application/json")
+
+@api.route("/send-email")
+class SendEmailResource(Resource):
+
+    def post(self):
+        """Send email to user when they are added to a new project"""
+        data = request.get_json()
+        username = data.get("username")
+        role = data.get("role")
+        project_name = data.get("projectName")
+
+        EmailService.send_email_to_user(username, role, project_name)

app/user/service.py

@@ -237,6 +237,30 @@ def get_github_user_information(access_token: str):
 class EmailService:
     """Class contains method to send alert using email"""
 
+    @staticmethod
+    def send_email_to_user(username: str, role: str, project_name: str):
+        """
+        Send email to user when they are added to a new project
+
+        Args:
+            username (str)
+            role (str): role of the user in the project
+            project_name (str)
+        """
+        user_email = UserService.get_by_username(username).email
+
+        if user_email:
+            mail_message = Message(
+                "You are added to a new project on ArboratorGrew",
+                recipients=[user_email]
+            )
+            mail_message.body = f"""Hello {username},\n\nYou are added to the project '{project_name}' 
+            on ArboratorGrew as a {role} role.\nHere is the link of the project
+            https://arborator.grew.fr/#/projects/{project_name}\n\nBest regards,\nArboratorGrew team."""
+            mail.send(mail_message)
+        else:
+            return
+
     @staticmethod
     def send_alert_email(title: str, alert: str):
         """