feat: 커뮤니티 글 등록/수정

- 유료 글에서만 gif를 등록할 수 있도록 수정

build.gradle.kts

@@ -70,6 +70,9 @@ dependencies {
     implementation("org.apache.poi:poi-ooxml:5.2.3")
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4")
 
+    // file mimetype check
+    implementation("org.apache.tika:tika-core:3.2.0")
+
     developmentOnly("org.springframework.boot:spring-boot-devtools")
     runtimeOnly("com.h2database:h2")
     runtimeOnly("com.mysql:mysql-connector-j")