fix of db table creation

internal/database/main.go

@@ -82,7 +82,7 @@ func InitDB(db *sql.DB) {
     );
 
     -- parent table
-    CREATE TABLE closed_positions (
+    CREATE TABLE IF NOT EXISTS closed_positions (
         id            INTEGER PRIMARY KEY AUTOINCREMENT,
         symbol        TEXT NOT NULL,
         currency_code TEXT NOT NULL,
@@ -94,7 +94,7 @@ func InitDB(db *sql.DB) {
     );
 
     -- child table, one row per close lot
-    CREATE TABLE close_entries (
+    CREATE TABLE IF NOT EXISTS close_entries (
         id                  INTEGER PRIMARY KEY AUTOINCREMENT,
         closed_position_id  INTEGER NOT NULL REFERENCES closed_positions(id),
         shares              INTEGER NOT NULL,