text: create table if not exists locations (
    id integer primary key,
    city text not null,
    country text not null,
    unique (city, country)
  );
  create table if not exists companies (
    id integer primary key,
    name text not null unique,
    webpage text not null unique,
    image_url text not null unique,
    location_id integer,
    foreign key (location_id) references locations (id)
  );
  create table if not exists roles (
    id integer primary key,
    name text not null,
    color text not null
  );
  create table if not exists tools (
    id integer primary key,
    name text not null,
    webpage text
  );
  create table if not exists projects (
    id integer primary key,
    name text not null,
    start_date text not null,
    end_date text,
    highlight text not null,
    client_id integer not null,
    vendor_id integer not null,
    foreign key (client_id) references companies (id),
    foreign key (vendor_id) references companies (id)
  );
  create table if not exists project_role_links (
    id integer primary key,
    project_id integer not null,
    role_id integer not null,
    foreign key (project_id) references projects (id),
    foreign key (role_id) references roles (id)
  );
  create table if not exists project_tool_links (
    id integer primary key,
    project_id integer not null,
    tool_id integer not null,
    foreign key (project_id) references projects (id),
    foreign key (tool_id) references tools (id)
  );
  