added createSchema.sql, implemented Dockerfile

backend/db/Dockerfile

@@ -0,0 +1,4 @@
+FROM postgres:15
+
+RUN mkdir /docker-entrypoint-initdb.d
+COPY createSchema.sql /docker-entrypoint-initdb.d

backend/db/createSchema.sql

@@ -0,0 +1,39 @@
+CREATE TABLE "user" (
+    username VARCHAR(32) PRIMARY KEY
+)
+
+CREATE TABLE game (
+    id SERIAL PRIMARY KEY,
+    score INTEGER NOT NULL,
+    playtime TIME NOT NULL,
+    date DATE NOT NULL,
+    username VARCHAR(32) NOT NULL FOREIGN KEY REFERENCES "user"
+)
+
+CREATE VIEW user_data AS (
+    SELECT
+        username,
+        max(score) AS highscore,
+        sum(score) AS total_score,
+        sum(playtime) AS total_playtime,
+        avg(score) AS average_score,
+        count(*) AS games_played
+    FROM game
+    GROUP BY username
+)
+
+CREATE VIEW lb_highscore AS (
+    SELECT username, max(score) AS highscore FROM game GROUP BY username ORDER BY highscore DESC
+)
+
+CREATE VIEW lb_highscore AS (
+    SELECT username, sum(score) AS total_score, FROM game GROUP BY username ORDER BY total_score DESC
+)
+
+CREATE VIEW lb_total_playtime AS (
+    SELECT username, sum(playtime) AS total_playtime FROM game GROUP BY username ORDER BY total_playtime DESC
+)
+
+CREATE VIEW lb_average_score AS (
+    SELECT username, avg(score) AS average_score FROM game GROUP BY username ORDER BY average_score DESC
+)