code: public List<Migration> getPendingMigrations() {
          List<String> appliedMigrations = getAppliedMigrationVersions();
  
          List<Migration> allMigrations = migrationResolver.resolve();
          List<Migration> pendingMigrations = new ArrayList<Migration>();
          for (Migration migration : allMigrations) {
              if(!appliedMigrations.contains(migration.getVersion())){
                  pendingMigrations.add(migration);
              }
          }
          return pendingMigrations;
      }
docs: Returns pending migrations.
  
  @return a sorted set of pending migrations