Estou usando Spring Boot para criar um web service RESTFul e um SOAP,  cada um em um módulo mas ambos em um único projeto. Então, eu decidi separar minha camada de domínio em um terceiro módulo já que é a mesma para ambos os tipos de web services e assim poderia reutilizar. Mesmo com a dependência entre os pacotes no Maven, quando vou executar a aplicação, ele questiona que, por exemplo, PessoaRepository, que é do módulo domínio e está sendo injetada via @Autowired no resource PessoaResource do módulo restful, não pôde ser injetada por não ser um Bean reconhecido pelo Spring:

Field pessoaRepository in br.com.tassioauad.restful.resource.PessoaResource required a bean of type 'br.com.tassioauad.domain.repository.PessoaRepository' that could not be found.

Minha separação ficou assim:

Módulo Domínio

pom.xml

    <?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>

        <groupId>br.com.tassioauad</groupId>
        <artifactId>domain</artifactId>
        <version>0.5</version>
        <packaging>jar</packaging>
        <name>domain</name>
        <description>Camada de Domínio</description>

        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
        </properties>

        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.5.10.RELEASE</version>
            <relativePath/>
        </parent>

        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-jpa</artifactId>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-annotations</artifactId>
                <version>RELEASE</version>
            </dependency>
            <dependency>
                <groupId>javax.validation</groupId>
                <artifactId>validation-api</artifactId>
            </dependency>
        </dependencies>

    </project>

PessoaRepository.java

public interface PessoaRepository extends CrudRepository<Pessoa, Integer>{

    //....

}

Módulo RESTFul

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>br.com.tassioauad</groupId>
    <artifactId>restful</artifactId>
    <version>0.5</version>
    <packaging>jar</packaging>

    <name>restful</name>
    <description>RESTFul API</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
        <relativePath/>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-hateoas</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-undertow</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>br.com.tassioauad</groupId>
            <artifactId>domain</artifactId>
            <version>0.5</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

PessoaResource.java

import br.com.tassioauad.domain.repository.PessoaRepository;

@RestController
@RequestMapping("/pessoa")
public class PessoaResource {

    @Autowired
    PessoaRepository pessoaRepository;

    //...
}

O que está faltando para que o Repository de um módulo seja reconhecido em outro módulo?

@EnableJpaRepositories("br.com.tassioauad.domain")
@SpringBootApplication
public class RestfulApplication {

    public static void main(String[] args) {
        SpringApplication.run(RestfulApplication.class, args);
    }
}

@EnableJpaRepositories("br.com.tassioauad.domain")
@EntityScan("br.com.tassioauad.domain")
@SpringBootApplication
public class RestfulApplication {

    public static void main(String[] args) {
        SpringApplication.run(RestfulApplication.class, args);
    }
}