add function to get database connection

dbi/dbi.go

@@ -0,0 +1,32 @@
+package dbi
+
+import (
+	"database/sql"
+	"os"
+
+	_ "modernc.org/sqlite"
+)
+
+func GetDbConn() (*sql.DB, error) {
+	const dbPath = "data/facultyactivity.sqlite"
+
+	_, err := os.Stat(dbPath)
+	if os.IsNotExist(err) {
+		if err := os.MkdirAll("data", 0755); err != nil {
+			return nil, err
+		}
+		db, err := sql.Open("sqlite", dbPath)
+		if err != nil {
+			return nil, err
+		}
+		if _, err := db.Exec(ActivityReportSchema); err != nil {
+			db.Close()
+			return nil, err
+		}
+		return db, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return sql.Open("sqlite", dbPath)
+}