diff --git a/uhabits-core/build.gradle b/uhabits-core/build.gradle
index 4f1dbd565..4dc458a31 100644
--- a/uhabits-core/build.gradle
+++ b/uhabits-core/build.gradle
@@ -24,6 +24,8 @@ dependencies {
     implementation 'com.google.dagger:dagger:2.11-rc2'
     implementation 'com.android.support:support-annotations:25.3.1'
     implementation 'com.google.auto.factory:auto-factory:1.0-beta3'
+    implementation 'com.google.code.findbugs:jsr305:3.0.2'
+    implementation 'org.apache.commons:commons-lang3:3.5'
 }
 
 sourceCompatibility = "1.8"
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/models/Checkmark.java b/uhabits-core/src/main/java/org/isoron/uhabits/models/Checkmark.java
similarity index 100%
rename from uhabits-android/src/main/java/org/isoron/uhabits/models/Checkmark.java
rename to uhabits-core/src/main/java/org/isoron/uhabits/models/Checkmark.java
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/models/Frequency.java b/uhabits-core/src/main/java/org/isoron/uhabits/models/Frequency.java
similarity index 100%
rename from uhabits-android/src/main/java/org/isoron/uhabits/models/Frequency.java
rename to uhabits-core/src/main/java/org/isoron/uhabits/models/Frequency.java
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/models/ModelObservable.java b/uhabits-core/src/main/java/org/isoron/uhabits/models/ModelObservable.java
similarity index 100%
rename from uhabits-android/src/main/java/org/isoron/uhabits/models/ModelObservable.java
rename to uhabits-core/src/main/java/org/isoron/uhabits/models/ModelObservable.java
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/models/Reminder.java b/uhabits-core/src/main/java/org/isoron/uhabits/models/Reminder.java
similarity index 100%
rename from uhabits-android/src/main/java/org/isoron/uhabits/models/Reminder.java
rename to uhabits-core/src/main/java/org/isoron/uhabits/models/Reminder.java
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/models/Repetition.java b/uhabits-core/src/main/java/org/isoron/uhabits/models/Repetition.java
similarity index 100%
rename from uhabits-android/src/main/java/org/isoron/uhabits/models/Repetition.java
rename to uhabits-core/src/main/java/org/isoron/uhabits/models/Repetition.java
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/models/Score.java b/uhabits-core/src/main/java/org/isoron/uhabits/models/Score.java
similarity index 100%
rename from uhabits-android/src/main/java/org/isoron/uhabits/models/Score.java
rename to uhabits-core/src/main/java/org/isoron/uhabits/models/Score.java
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/models/WeekdayList.java b/uhabits-core/src/main/java/org/isoron/uhabits/models/WeekdayList.java
similarity index 100%
rename from uhabits-android/src/main/java/org/isoron/uhabits/models/WeekdayList.java
rename to uhabits-core/src/main/java/org/isoron/uhabits/models/WeekdayList.java