text: CREATE TABLE Users (ID serial PRIMARY KEY, USERNAME VARCHAR(255) UNIQUE NOT NULL, PROFILEIMG TEXT, ALT VARCHAR(255));
  
  INSERT INTO Users (USERNAME, PROFILEIMG, ALT) VALUES ('Alice', 'images/profiles/alice.jpeg', 'Alice');
  INSERT INTO Users (USERNAME, PROFILEIMG, ALT) VALUES ('Bob', 'images/profiles/bob.jpeg', 'Bob');
  INSERT INTO Users (USERNAME, PROFILEIMG, ALT) VALUES ('Charlie', 'images/profiles/charlie.jpeg', 'Charlie');
  INSERT INTO Users (USERNAME, PROFILEIMG, ALT) VALUES ('Dave', 'images/profiles/dave.jpeg', 'Dave');
  INSERT INTO Users (USERNAME, PROFILEIMG, ALT) VALUES ('Eve', 'images/profiles/eve.jpeg', 'Eve');
  
  CREATE TABLE Messages (
  	ID serial PRIMARY KEY, 
  	MESSAGE_TEXT text NOT NULL, 
  	CREATED_ON TIMESTAMP NOT NULL, 
  	FROM_USER INT NOT NULL,
  	MENTION_USER_ID INT,
  	FOREIGN KEY (FROM_USER) REFERENCES Users (ID), 
  	FOREIGN KEY (MENTION_USER_ID) REFERENCES Users (ID)
  	);