add unicode locale generation to Dockerfile

before the change, unicode characters were displayed in console as question marks

Dockerfile

@@ -12,6 +12,13 @@ RUN  mkdir ${DATA_PATH}
 RUN mkdir ${DATA_PATH}/logs && \
     ln -sf ${DATA_PATH}/logs ${CONFIG_PATH}
 
+# Generate unicode locale so that cyrillic characters display properly
+RUN apt-get update -y && apt-get install -y locales && \
+    echo en_US.UTF-8 UTF-8 > /etc/locale.gen && \
+    dpkg-reconfigure --frontend=noninteractive locales
+ENV LANG en_US.UTF-8
+
+
 VOLUME ${DATA_PATH}