I want to create a simple communication APP, that registered users that I promote to SENDERS, can send fixed-type short messages (like push notification) to a selected user, or to a group that ADMIN creates, which contain many users.
The APP can have 3 different types of users:
1) Simple APP USER
That is a registered user of the Mobile App, that can ONLY receive and read short messages of all SENDERS, in a chronological/time order that was received (like a news feed).
That is a registered user of the Mobile App, that is promoted from ADMIN in the database as a SENDER that can send short fixed-type messages to the Simple APP USERS (to selected user/s, or to group/s of users, that ADMIN can create in his database).
The SENDER knows only specific usernames, or specific groupnames, that ADMIN tells him to use when send messages.
That is ME, that create/delete users, create/delete groups of users, view list of registered users, edit some data or settings e.t.c. ...in a database that contains ALL the registered APP USERS (maybe in a control panel, or a control page that only ADMIN have access).
*** ADMIN creates username and password for users (after they request login details for the Mobile APP) and send these details by e-mail, to make them registered users that are able to LOGIN to the APP.
In order someone to be able to LOGIN to the APP, he needs to have a username that exist in the LIST of users, in the database that ADMIN operates.
The App "users database" is very simple and small, because any user can have ONLY 4 info.
Username, Password, Nickname and a Status (if he is SENDER or not). Nothing more.
All these 4 info are decided and created from ADMIN in the database (a control page) that he operates.
The main Mobile APP screen, that both SENDER and Simple APP USER can see, is just a fixed area for sending and/or reading messages (push notification).