readConfig function
Implementation
Config readConfig(String configPath) {
var configRaw = json.decode(File(configPath).readAsStringSync());
// Verify config integrity
assert(configRaw is Map<String, dynamic>);
assert(configRaw["default"] != null);
assert(configRaw["default"]["vars"] != null);
assert(configRaw["environments"] is Map<String, dynamic>);
var config = Config.fromJson(configRaw);
return config;
}