Add liquibase to Spring Boot project. Generate changelog from existed DB in IDEA > Gradle > Tasks > liquibase > generateChangelog. Before make generateChangelog be sure that directory liquibase is exists

2018_12_14--01-dictionary.groovy

# current file location: src/main/liquibase/v-1.0/2018_12_14--01-dictionary.groovy
databaseChangeLog() {
    changeSet(id: '1547828693315-1', author: 'dmitry_tkachenko (generated)') {
        createSequence(cacheSize: 0, cycle: false, incrementBy: 1, maxValue: 9999999999999999999999999999, minValue: 1, ordered: false, sequenceName: 'CHANNEL_SEQ', startValue: 3)
    }
    
    changeSet(id: '1547828693315-41', author: 'dmitry_tkachenko (generated)') {
        createTable(tableName: 'TEMPLATE_CHANNEL_TAB') {
            column(name: 'TEMPLATE_ID', type: 'NUMBER(19, 0)') {
                constraints(nullable: false)
            }
            column(name: 'CHANNEL_ID', type: 'NUMBER(19, 0)') {
                constraints(nullable: false)
            }
        }
    }
    ...
    
}

2018_12_14--01-dictionary.yml

# current file location: src/main/liquibase/v-1.0/2018_12_14--01-dictionary.yml
databaseChangeLog:
    -   changeSet:
            id: drop_unique_group_tab_constraint
            author: rtln
            changes:
                -   dropUniqueConstraint:
                        constraintName: uk_sw62vm5lf3sdy93djsk40i3rh
                        tableName: group_tab
    -   changeSet:
            id: 1550074683089-3
            author: dmitry_tkachenko (generated)
            changes:
                -   createSequence:
                        cacheSize: 0
                        maxValue: 9999999999999999999999999999
                        sequenceName: DICTIONARY_FIELD_SEQ
                        startValue: 1

build.gradle

plugins {
    id 'java'
    id 'groovy'
    id 'org.springframework.boot' version '2.0.6.RELEASE'
    id 'org.liquibase.gradle' version '2.0.1' // required
}

apply plugin: 'io.spring.dependency-management'

dependencies {
    compile('org.springframework.boot:spring-boot-starter-jetty') {
        exclude group: 'org.eclipse.jetty.websocket'
    }
    compile('org.springframework.boot:spring-boot-starter-web') {
        exclude module: 'spring-boot-starter-tomcat'
    }
    compile 'org.springframework.boot:spring-boot-starter-data-jpa'
    // compile "org.liquibase:liquibase-core" - don't include for manual star liquibase
    ...
    
    liquibaseRuntime 'org.liquibase:liquibase-core' // required
    liquibaseRuntime 'org.liquibase:liquibase-groovy-dsl:2.0.1' // required
    liquibaseRuntime "com.oracle:ojdbc7:${oracleJdbcVersion}" // required
    liquibaseRuntime 'ch.qos.logback:logback-classic'
}

liquibase {
    activities {
        main {
            def file = new File("${projectDir}/liquibase.properties")
            if (file.exists()) {
                def props = new Properties()
                InputStream is = new FileInputStream(file)
                props.load(is)
                is.close()

                changeLogFile props['changeLogFile']
                url props['url']
                username props['username']
                password props['password']
            } else {
                println "Add ${projectDir}/liquibase.properties if you want use liquibase plugin"
            }
        }
    }
}

liquibase.properties

changeLogFile=src/main/liquibase/root.groovy # or changeLogFile=src/main/liquibase/root.yml
url=jdbc:oracle:thin:@localhost:1521/xe
username=test
password=test

root.groovy

# current file location: src/main/liquibase/root.groovy
databaseChangeLog() {
  include(file: "v-1.0/2018_12_14--01-dictionary.groovy", relativeToChangelogFile: "true")
}

root.yml

# current file location: src/main/liquibase/root.yml
databaseChangeLog:
    -   include:
            file: src/main/liquibase/v-1.0/2018_12_14--01-dictionary.yml