How to set permissions with Docker Build? error checking context: 'no permission to read from...'

I firstly encountered

ERROR: Couldn't connect to Docker daemon at http+docker://localunixsocket - is it running?

problem when I try to run docker-compose build.

version: '3.1'

services:
  client:
    build: .
    volumes:
      - "./client:/app"
    ports:
      - "3031:3000"
    depends_on:
      - api

  api:
    build: .
    volumes:
      - "./api:/app"
    ports:
      - "3003:3000"
      - "9229:9229"
    depends_on:
      - db

  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: example
      MYSQL_DATABASE: users
      MYSQL_USER: test
      MYSQL_PASSWORD: test1234
    ports:
      - "3307:3306"
    volumes:
      - ./docker/data/db:/var/lib/mysql

I made small changes to one repo by adding Docker debug options. After looking at this and many SO posts, I realized that I should try docker build.

docker build -f="Dockerfile" .

I got error

error checking context: 'no permission to read from '/home/miki/mysql-registration-passport/docker/data/db/ca-key.pem''.

These are files with permissions

drwxr-xr-x  9 miki miki 4096 мај  7 07:56 ./
drwxr-xr-x 88 miki miki 4096 мај  7 06:20 ../
drwxr-xr-x  6 miki miki 4096 мај  6 08:51 api/
drwxr-xr-x  5 miki miki 4096 мај  6 10:41 client/
drwxr-xr-x  3 root root 4096 мај  6 10:41 docker/
-rw-r--r--  1 miki miki  543 мај  7 07:37 docker-compose.yml
-rw-r--r--  1 miki miki   64 мај  6 08:45 Dockerfile
drwxr-xr-x  8 miki miki 4096 мај  6 08:45 .git/
drwxr-xr-x  2 miki miki 4096 мај  6 08:45 .github/
-rw-r--r--  1 miki miki   55 мај  6 08:45 .gitignore
drwxr-xr-x  3 miki miki 4096 мај  6 08:45 .idea/
-rw-r--r--  1 miki miki 3462 мај  6 08:45 README.md
drwxr-xr-x  2 miki miki 4096 мај  6 08:45 .vscode/

How to set docker folder permissions? I am on Ubuntu 18.04.