Add .gitignore for generated database files and implement database connection functionality

internal/database/.gitignore

@@ -0,0 +1,2 @@
+# Ignore the generated files to avoid git conflicts
+dbgen/

internal/database/connect.go

@@ -0,0 +1,36 @@
+package db
+
+import (
+	"database/sql"
+
+	"github.com/eduardolat/pgbackweb/internal/config"
+	"github.com/eduardolat/pgbackweb/internal/logger"
+	_ "github.com/lib/pq"
+)
+
+func Connect(env *config.Env) *sql.DB {
+	db, err := sql.Open("postgres", *env.PBW_POSTGRES_CONN_STRING)
+	if err != nil {
+		logger.FatalError(
+			"Could not connect to DB",
+			logger.KV{
+				"error": err,
+			},
+		)
+	}
+
+	err = db.Ping()
+	if err != nil {
+		logger.FatalError(
+			"Could not ping DB",
+			logger.KV{
+				"error": err,
+			},
+		)
+	}
+
+	db.SetMaxOpenConns(10)
+	logger.Info("Connected to DB")
+
+	return db
+}