Local Testnets – How to Create a Local USDT Testnet

I want to create a local testnet on which I can move USDT (test coins) between wallets.

I managed to create a ETH testnet inside Docker. In the docker-compose.yml below, the lines between # ETH testnet setup (start) and # ETH testnet setup (end) are responsible for that.

version: '3'

services:
#
# BTC testnet setup (start)
#
  node:
    image: ulamlabs/bitcoind-custom-regtest:latest
  electrumx:
    image: lukechilds/electrumx:latest
    links:
      - node
    ports:
      - "51001:50001"
      - "51002:50002"
    environment:
      - NET=regtest
      - COIN=BitcoinSegwit
      - DAEMON_URL=http://test:test@node:19001
  explorer:
    image: ulamlabs/btc-rpc-explorer:latest
    links:
      - node
      - electrumx
    ports:
      - "3002:3002"
    environment:
      - BTCEXP_HOST=0.0.0.0
      - BTCEXP_BITCOIND_URI=http://test:test@node:19001
      - BTCEXP_ELECTRUMX_SERVERS=tls://electrumx:50002
      - BTCEXP_ADDRESS_API=electrumx
#
# BTC testnet setup (end)
#


#
# ETH testnet setup (start)
#
  geth:
    image: ulamlabs/geth-poa-testnet:latest
    environment:
      - ETH_PASSWORD=QfdxTYxkwASj
      - ETH_PRIVATE_KEY=0d0b4c455973c883bb0fa584f0078178aa90c571a8f1d40f28d2339f4e757dde
      - ETH_ADDRESS=0c56352F05De44C9b5BA8bcF9BDEc7e654993339
    ports:
      - 8178:8178
      - 8546:8546
    volumes:
      - ./genesis.json:/app/genesis.json

  postgres:
    image: postgres:12
    command: postgres -c 'max_connections=500'
    environment:
      - POSTGRES_HOST_AUTH_METHOD=trust

  blockscout:
    image: ulamlabs/blockscout:latest
    links:
      - geth
      - postgres
    ports:
      - 4000:4000
    environment:
      - DATABASE_URL=postgresql://postgres:@postgres:5432/postgres?ssl=false
      - ETHEREUM_JSONRPC_VARIANT=geth
      - ETHEREUM_JSONRPC_HTTP_URL=http://geth:8178
      - ETHEREUM_JSONRPC_WS_URL=ws://geth:8546
      - MIX_ENV=prod
      - BLOCKSCOUT_HOST=localhost
      - COIN=eth
      - NETWORK=POA
      - SUBNETWORK=Local Testnet

#
# ETH testnet setup (end)
#

The file ./genesis.json:/app/genesis.json contains the following:

{
    "config": {
        "chainId": 5555,
        "clique": {
            "period": 60,
            "epoch": 30000
        },
        "homesteadBlock": 0,
        "eip150Block": 0,
        "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "eip155Block": 0,
        "eip158Block": 0,
        "byzantiumBlock": 0,
        "constantinopleBlock": 0,
        "petersburgBlock": 0,
        "istanbulBlock": 0,
        "muirGlacierBlock": 0
    },
    "extraData": "0x00000000000000000000000000000000000000000000000000000000000000000c56352F05De44C9b5BA8bcF9BDEc7e6549933390000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
    "alloc": {
        "411167FeFecAD12Da17F9063143706C39528aa28": {
            "balance": "0x200000000000000000000000000000000000000000000000000000000000000"
        }
    },
    "nonce": "0x0",
    "timestamp": "0x5eaa7b09",
    "gasLimit": "0x47b760",
    "difficulty": "0x1",
    "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "coinbase": "0x0000000000000000000000000000000000000000",
    "number": "0x0",
    "gasUsed": "0x0",
    "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

As far as I understand,

• no USDT test coins are being mined in this testnet and
• in order to have USDT test coins I need to add ERC20 support to the ETH (geth) testnet.

How do I need to modify the above docker-compose.yml and/or genesis.json files in order to add ERC20/USDT support to my ETH testnet?