diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index 81daf5ef..5858055d 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -22,6 +22,7 @@
             <option value="$PROJECT_DIR$/feature/library" />
             <option value="$PROJECT_DIR$/feature/scan" />
             <option value="$PROJECT_DIR$/feature/search" />
+            <option value="$PROJECT_DIR$/source" />
             <option value="$PROJECT_DIR$/utils" />
           </set>
         </option>
diff --git a/source/src/main/java/one/nem/lacerta/source/database/placeholder b/source/src/main/java/one/nem/lacerta/source/database/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/source/src/main/java/one/nem/lacerta/source/file/placeholder b/source/src/main/java/one/nem/lacerta/source/file/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/source/src/main/java/one/nem/lacerta/source/jgit/placeholder b/source/src/main/java/one/nem/lacerta/source/jgit/placeholder
new file mode 100644
index 00000000..e69de29b