fill readonly PostsAPI

src/main/kotlin/com/github/insanusmokrassar/postssystem/core/api/PostsAPI.kt

@@ -0,0 +1,12 @@
+package com.github.insanusmokrassar.postssystem.core.api
+
+import com.github.insanusmokrassar.postssystem.core.post.Post
+import com.github.insanusmokrassar.postssystem.core.post.PostId
+import com.github.insanusmokrassar.postssystem.core.content.ContentId
+import org.joda.time.DateTime
+
+interface PostsAPI {
+    suspend fun getPostById(id: PostId): Post?
+    suspend fun getPostsByContent(id: ContentId): List<Post>
+    suspend fun getPostsByDates(from: DateTime? = null, to: DateTime? = null): List<Post>
+}

src/main/kotlin/com/github/insanusmokrassar/postssystem/core/post/Post.kt

@@ -1,4 +1,4 @@
-package com.github.insanusmokrassar.postssystem.core
+package com.github.insanusmokrassar.postssystem.core.post
 
 import com.github.insanusmokrassar.postssystem.core.content.Content
 
@@ -7,4 +7,6 @@ typealias PostId = String
 interface Post {
     val id: PostId
     val content: List<Content>
+
+    val meta: PostMetaInfo
 }

src/main/kotlin/com/github/insanusmokrassar/postssystem/core/post/PostMetaInfo.kt

@@ -0,0 +1,9 @@
+package com.github.insanusmokrassar.postssystem.core.post
+
+import org.joda.time.DateTime
+
+interface PostMetaInfo {
+    val postId: PostId
+    val creationDate: DateTime
+    val modificationDate: DateTime
+}