redpen-cc/redpen

Hi. I'm trying to use redpen and I probably doing something wrong with Spelling validator. My redpen-conf-en.xml is

<redpen-conf lang="en">
    <validators>
        <!--Rules on expressions-->
        <validator name="SymbolWithSpace"/>
        <validator name="SuccessiveWord" />
        <validator name="FrequentSentenceStart"/>
        <validator name="UnexpandedAcronym"/>
        <validator name="WeakExpression"/>
    <validator name="Spelling">
            <property name="dict" value="redpen-spelling-dict"/>
        </validator>

        <!--Rules on sections and paragraphs-->
        <validator name="SpaceBeginningOfSentence" />
        <validator name="ParenthesizedSentence"/>
        <validator name="DuplicatedSection" />
        <validator name="DoubleNegative" />
        <validator name="SuccessiveSentence" />

        <!--Rules on symbols and terminologies-->
        <validator name="InvalidSymbol"/>
        <validator name="Spelling"/>
        <validator name="Hyphenation"/>
        <validator name="NumberFormat"/>

        <!--Load JavaScript validators-->
        <validator name="JavaScript" />
    </validators>
    <symbols>
        <symbol name="LEFT_SINGLE_QUOTATION_MARK" value="'" invalid-chars="‘" before-space="false" after-space="false" />
        <symbol name="RIGHT_SINGLE_QUOTATION_MARK" value="'" invalid-chars="’" before-space="false" after-space="false" />
    </symbols>
</redpen-conf>

and my redpen-spelling-dict is

RStudio
gapminder
summative

but when I run redpen -f markdown _episodes/01-design.md | grep RStudio I got

01-design.md:26: ValidationError[Spelling], Found possibly misspelled word "page-long". at line:      For example,     the lesson might be for people who have taught themselves     how to write page-long statistical analyses in R using RStudio,     but have never written functions or run programs from the Unix shell prompt.
01-design.md:26: ValidationError[Spelling], Found possibly misspelled word "page-long". at line:      For example,     the lesson might be for people who have taught themselves     how to write page-long statistical analyses in R using RStudio,     but have never written functions or run programs from the Unix shell prompt.
01-design.md:26: ValidationError[Spelling], Found possibly misspelled word "RStudio". at line:      For example,     the lesson might be for people who have taught themselves     how to write page-long statistical analyses in R using RStudio,     but have never written functions or run programs from the Unix shell prompt.
01-design.md:26: ValidationError[Hyphenation], This phrase should be hyphenated (ie: "how-to"). at line:      For example,     the lesson might be for people who have taught themselves     how to write page-long statistical analyses in R using RStudio,     but have never written functions or run programs from the Unix shell prompt.