avoid overwrite old database value when republish smart contract

contracts/currency/currency.cpp

@@ -39,8 +39,12 @@ using namespace TOKEN_NAME;
 
 extern "C" {
     void init()  {
+       account owned_account;
+       //Initialize currency account only if it does not exist
+       if ( !accounts::get( owned_account, N(currency) )) {
           store_account( N(currency), account( currency_tokens(1000ll*1000ll*1000ll) ) );
        }
+    }
 
     /// The apply method implements the dispatch of events to this contract
     void apply( uint64_t code, uint64_t action ) {

contracts/infinite/infinite.cpp

@@ -41,8 +41,12 @@ using namespace infinite;
 
 extern "C" {
     void init()  {
+       account owned_account;
+       //Initialize currency account only if it does not exist
+       if ( !accounts::get( owned_account, N(currency) )) {
           store_account( N(currency), account( currency_tokens(1000ll*1000ll*1000ll) ) );
        }
+    }
 
     /// The apply method implements the dispatch of events to this contract
     void apply( uint64_t code, uint64_t action ) {

contracts/storage/storage.cpp

@@ -101,9 +101,13 @@ using namespace TOKEN_NAME;
 
 extern "C" {
     void init()  {
+       account owned_account;
+       //Initialize storage account only if it does not exist
+       if ( !accounts::get( owned_account, N(storage) )) {
           // How do we initialize the storage capacity? By how much here?
           accounts::store( account( storage_tokens(1000ll*1000ll*1000ll) ), N(storage) );
        }
+    }
 
     /// The apply method implements the dispatch of events to this contract
     void apply( uint64_t code, uint64_t action ) {